Would the 6mm ARC have been the best universal cartridge (rifle, LMG, HMG) for WWII?German doctrine because they used their rifle cartridge for all of that already. I've yet to find a better one.
The MG34/42 was also an AA gun, so probably not ideal. For Americans, a light BAR chambered in 6mm would have been awesome though.
>>64547918>The MG34/42 was also an AA gun, so probably not idealCan't really can't much worse for that, can it? The Germans realized pretty fast that anything under 15mm is mostly just used for moral purposes there.
6.5 Grendel is the universal cartridge.
>>64547888Basically any modern cartridge would have been better than any WW2 cartridge.>>64548054>That bullet is half a millimeter too small!
>>64548068We're looking for a champion here, anon.>>64548054Seems to do worse while allowing for less ammo to be carried and loaded though.
>>645478886mm SAW did the same thing and works better in a belt feed, along with allowing more magazine capacity. Unfortunately instead we got the worst 5.56 load known to man - M855 instead, along with a M249 as a replacement.
>>64548101>6mm SAW did the same thingDoes it though?
>>64547888Any modern intermediate cartridge wipes the floor with any WWII full-power round. Depending on how "general" you intend it to be, 5.56 or 5.45 might still be better since they're lighter and do the same thing at typical engagement ranges, but the difference isn't that big and 6mm ARC is better suited to indirect MG fire and barrier blindness and the like. I don't know anything about German doctrine though.
>>64548213>Depending on how "general" you intend it to be, 5.56 or 5.45 might still be better since they're lighter and do the same thing at typical engagement rangesAnon, 5.56 would never work at the ranges required for an HMG.
>>645480686.5 is the best mm>>64548092get FN IWS .264https://desuarchive.org/k/thread/64326816
>>64548234>get FN IWS .264I've yet to find a way to travel through time, anon
>>64548245What is the OP
>>64548249Preparation for time-travel.
>>64548232Yeah. The HMG requirement is what really forces us to compromise here. I looked a bit more, and it seems the Germans had an M2 equivalent - the MG131 in 13x64mmB - that they mostly used on planes but was experimentally made into a man-portable HMG. While something like this might offer an advantage today due to the availability of the M8 API, the normal 7.92 Mauser or 8x63mm Swedish might be better for WWII HMGs. So a two-caliber system with 5.55/6ARC/Grendel on the rifle and MMG end and something heavier on the HMG end. If we're keeping the HMG criterion, then something in the .308 class. 6.5 Creedmoor is nice.
>>64548151Yes.
>>64548285>Yeah. The HMG requirement is what really forces us to compromise here.In general, the MG role is more important than the rifle role, hence the 8mm Mauser.The point of the exercise is kinda to avoid the host of problems multiple calibers bring with them.
>>64548234What an elucidative picture. Thanks anon. So much comes together. So it’s a 6.5 sneed with a shorter case, maybe running at slightly higher than normal pressures? So that should duplicate 6.5 ballistics. But what does FN gain from shortening the cartridge by what looks like about 0.3”? Why not just use a 6.5 creedmoor, or if they’re gonna make their own wildcat cartridge anyways, anything else but with the 2.8” COAL?>>64548101Came in to say this. Yeah the 6 ARC is basically 6 SAW but with slightly higher energy and in a shorter (but wider) package. Though I can’t remember why 6mm SAW went nowhere - perhaps there was a good reason, lol, one germane to this thread.>>64548213> Any modern intermediate cartridge wipes the floor with any WWII full-power roundDepends what you mean by ‘sweeps the floor with’. And btw, “ww2 full power cartridges” are very much modern-day full power cartridges. 30-06, 8mm Mauser, etc
>>64548292Do we though?
>>64548346>Yeah the 6 ARC is basically 6 SAW but with slightly higher energy and in a shorter (but wider) package.Would probably be best to go with a longer (but less wide) version, to stack more rounds.Though I guess that'd be less weight efficient?Definitely needs the extra power though, if you're gonna go for the HMG role.
>>64548299Yeah, I think .308 or 6.5 Creedmoor (especially the latter) are really good for that. Very nice balance. Reportedly this cartridge >>64548234 will compete with 6.5 Creedmoor but for shorter barrels, which while cool isn't terribly important for WWII.Neat thread idea by the way.
>>64548358>6.5 CreedmoorHow does the energy of Creedmoor compare to ARC at a mile?
>>64548346>Though I can’t remember why 6mm SAW went nowhereBecause army didn't want a third round, so instead of having a thing that works exactly as designed we ended up with more 5.56.
>>64548356>thinner case to stack more roundsYeah, the 6 ARC is damn near as wide as a 308. The new pmags for the Surefire ICAR lower only hold 25. They appear to be about the same length as a PMAG 30>is this less weight efficient?Stick ‘em in a quad stack and you’re at maximum weight efficiency. This also kinda gives you a gun capable of LMG schedules/strings of fire, but without the pain in the ass of carrying and replenishing belts and the heavy belt-fed MG they go with. Let’s say a 10mm case head diameter, 70 round mags (desert tech style and with nested springs), and a nice and slow constant recoil action, running around 500-550rpm.
>>64548356> to stack more roundsShort fat shells with sharp wide bottlenecks don't work well in belt feds. >Though I guess that'd be less weight efficient?Not my any meaningful amount. Maybe it mattered more decades ago when powder wasn't as consistent for precision shooting but nowadays case capacity is case capacity no matter how much you stretch it into a cylinder, within reason.
>>64548346>elucidativeback to plebbit, Brainlet dumbfuck.
>>64548234>6.5 is the best mm>>64548068I would like to see an expansion to exit wound ratio test performed to decide if there's a bleed out factor, which applies for hunting and military purposes. Pretty sure the Grendel has the better barrel life too.But if Stoner were alive today he would have gone for the .224 Valkyrie because it has less than half the recoil and lends itself better to automatic fire.
>>64548420Reeee. Look at my google search history. I double checked to make sure that was a word before I used it.
>>64548403>Stick ‘em in a quad stack and you’re at maximum weight efficiencyCan't run something so unreliable in a military, anon
>>64548432>'i-i need validation from posting online'back to the containment colonyGet Out Of Here
>>64548454No, I just want to be sure the words I’m using are actual words. >>64548440Honestly, if quad stacks aren’t adequately reliable in their current incarnation (they might be, idk, the surefires ran fine and I haven’t heard anything negative about the desert techs), then we ought to throw billions of dollars into perfecting them. Cause if it’s a solvable problem, and if they can be made adequately reliable, this can conceivably push the assault rifle quite deep into LMG territory and obsolete the belt fed 5.56. Just give everyone a 7lb LMG with a 70-80 round mag and tweak doctrine around that. The late Jim Sullivan thought so, too.
>>64548473We're still in WWII territory for this thread, anon. I could explain to a physicist back then where to look for uranium and what the easiest solution to some of their issues with it back then were, but how are they supposed to figure out something we still haven't figured out ourselves?
>>64548428Grendel has better barrel life because it's slower than piss. Might as well shoot subsonic .300 if that's your only criterion.Stoner would absolutely recommend .224 Valkyrie today because it actually fits in an AR-15. 6mm ARC uses the 7.62x39 bolt face which is unsafe for a standard AR-15 sized bolt. If you're going to build some sort of goofy hybrid AR-10/15 to fit a bigger bolt without breaking AR-15 parts compatibility you might as well go for broke and stick a magnum sized bolt in there for a WSSM chambering.
>>64548482>it’s still WWIIDammit, I forgot. But yeah in that case just a regular 6 ARC would work well, since intermediates were useful in ww2. Better than anything else that was fielded, and with a higher capacity.
>>64548495>If you're going to build some sort of goofy hybrid AR-10/15>AR in WWIINigger you need mass produced, cheap and reliable rifles. You're not gonna fuck around with ARs in 1940. Just save yourself the trouble and make some kind of proto-G3.No gas system, no problems. Just stamping.
>>64548501The dude I was responding to was talking about Eugene Stoner, retard. How much gunsmithing was Stoner doing in the 30s and 40s?
>>64548513>The dude I was responding to was talking about Eugene StonerIn relevance to the topic at hand, yes.
>>64548519And my comment was relevant to the topic of Stoner's opinions. Deal with it.
>>64548527> of Stoner's opinions...in relation to the topic at hand.
Autism.
>>64548495Grendel is slow unless you load it to the same weights as 6ARC. Then a really funny thing happens.
>>64549996Then you have 6 ARC with worse external ballistics.
>>64548537No just a bunch of team sports fan besties objectifying their fav 6 mm
>>64550178I just wish they'd give reasons for it at least.
>>64547888Bump, because it's an actually interesting brand of autism for once (mine).
>>64548362It's much higher. What are you shooting at from a mile away, though?
>>64551379HMG fire in German doctrine was mostly about controlling space, though sometimes they were used as quasi light artillery.
>>64551423They would benefit more from better doctrine than a better cartridge.
>>64551427Weird, because it worked really well and they were far from the only ones who ended up using it like that. German doctrine was pretty influential for a reason, anon.
>>64551427It may seem unusual to an American but the UK uses GPMGs for plunging fire to this day. Not saying that the should, but it wasn't a bad doctrine at the time.
>>64551446Based plungers
>>64550518Fist(bump)ing each other just like in /hg/ /arg/That's their reason
>>64552262My Dad Could Beat Up Your Dad: Ammo Edition
The round casing being too fat means less rounds in the magazine.
>>64553997Make the casing longer and thinner then?
>>64554019Would that actually change anything about the ballistics/reliability?Seems like an obvious choice.
>>64554919If you reduce the diameter by half you'll need to increase the length by more than double to get the same volume, but as long as volume is the same, performance will be similar.
>>64554919If your case capacity stays the same, no, not really.
>>64554941>>64554944So obviously, there are dimishing returns, but what would be the best ratio for 34-35 grains of water?
>>64554960That's about 2.275 cubic centimeters, the equation for the volume is a cylinder is length*pi*(radius^2). Plug in some numbers until you get a shape you like, and leave a little extra to account for taper.
>>64547888Yeah just make a 6mm arc Draco, AKm, RPK etcThen you can have your next round up be a big one like .408 cheytac for the belt feds and snipersIt outshoots 50bmg with half the recoil and shits on 338lm
>>64555472I guess the question would be, how long and thin can you go until it becomes too unstable to reliably extract or load or the weight doesn't become worth the effort anymore.
>>64555878.416 Barrett is better.
I used to think 6 ARC was cool, but then I learned that it has AK casing levels of taper. This means it needs banana magazines to be reliable. The straight mags are prone to jamming and are also super long.
>>64556252>7.62x39 taperNope. It’s got less taper than the 6.5 Grendel. The shoulder is a bit wider. I have seen guys running 7.62x39 AR mags for 6 ARC. Makes me scratch my head.
>>64555472Calculating the volume using two conical frustums and a cyclinder will give exact results (assuming uniform wall thickness, like a NAS3 case). The cylinder up the shoulder is one big frustum, then the shoulder to the neck is another smaller frustum, and the neck is a cylinder.>>64554960Best in what terms?
>>64554960>>64557603>Best in what terms?I think the first poster meant "best" as in what will give you the most convenient shape for autoloading and handling, and that's a little subjective and depends on a lot of different things, but from a physics standpoint a squat case that is short and wide is supposedly ideal for combustion consistency, which was one of 6mm PPC's findings. 6mm ARC is very similar to 6mm PPC in this regard.
>>64547888>Would the 6mm ARC have been the best universal cartridge (rifle, LMG, HMG) for WWII?No because the cartridge is heavily bottlenecked, meaning that the base area is huge, meaning that the gas pressure on the bolt is huge, meaning that the rifle would be unneccessary heavy.
>.22 CHeetahOP BTFO
>>64558023>but from a physics standpoint a squat case that is short and wide is supposedly ideal for combustion consistency, which was one of 6mm PPC's findings. 6mm ARC is very similar to 6mm PPC in this regard.Probably not worth the decreased ammo count in your mag though, right?
>>64558137>meaning that the base area is huge, meaning that the gas pressure on the bolt is huge,This seems inherently contradictory.
>>64558137It's literally 0.7mm smaller than 8mm Mauser you retard
>>64551446Americans still do that but we've become so dominant we don't really have to fight pitched battles so denying light infantry mobility via GPMGs isn't really something we do, off a tripod at least.Airforcelets need to understand.
>>64548473this already exists. People don't use it because they're scared of change and there are a lot of sunk costs in normal magazines, though these are objectively better. LSAT's project manager also proposed lightweight beltfeds for everyone btw. Technologically it's absolutely possible.
If they designed 6.8 SPC to use a .243 bullet, or hell even a .264 bullet, instead we could have avoided all this mess over 20 fucking years ago
>>64560494Picrel, 4th from the left. Someone wildcatted it. I agree, it could’ve been great. And it can run at higher pressures than the 6.5 grendel for the same bolt thrust. .277, and with that lackluster ogive length, was really a terrible choice for the 6.8SPC. 7mm was also considered, but Atleast they didn’t go full retard with that caliber. They endeavored to give the ar15 better external ballistics than was possible with 5.56, and ended up with a cartridge with *less* sectional energy and an even worse bullet shape. wtf were these people thinking?>>64558137Meh, the gun wouldn’t have to be any bigger or heavier than an AK. Their cartridges share the same base diameter, and I’m sure an AK can handle a 60kpsi 7.62x39.
>>64558805He means bolt thrust. Pressure is in pounds per square inch, case head area is in square inches. Square inches cancel out and you get pounds of force against the bolt head. He's retarded though, you can ignore his opinion.
>>64560494>>64560743>6.8 SPC to use a .264 bullet>4th from the lefthm, nice. I'm a 6.5 Grendel and >>64548234 FN IWS .264 proponent but could get on board with that wildcat. Why 144 gr though?
When I see the OP's pic I see a delicate round that would bend and jam a gun easier than the smoother transitions on the 5.56 and .308 round.The ammo is part of many mechanical devices, not just a ballistic nerd's dream.I want a round banged around by monkeys in logistics without falling apart then fed 20 degrees off center by some abused machinegun that should have been retired before its recent deployment, and everything still cycling.Not a round 20% better on a benchrest but jams up guns.These fancy rounds give way too much leverage to the bullet against the brass cartridge sticking out that long, and the sharp shoulder certainly more prone to misfeed in advese conditions.The traditional rounds all have better angles for feeding large numbers of rounds with imperfections after imperfect storage and transport and used in adverse conditions by barely maintained weapons fielded well past their lifespans prime.
>>64560488Show me some reliability tests, anon.I wish to see the >brrrrrrrrrrrrrr
>>64547888>6mm ARC as a universal cartridgeIt really is. It can do everything except big game, and still up to impala at 350yrds.
>>64562374This is the mind of an intelligent man who isn't very smart in the practical sense.>le form is le bad>old rounds are le betterWhy not just suggest changing the round then if the ballistics are great and you can't suggest a better option? A mind that doesn't naturally work towards solutions seems alien to me.
>>64561058>He means bolt thrust.Esblane
>>645478886.5×55mm Swedish
>>64562453Try 800 buttercup.
>>64563737Meh
>>645478887.92mm is the calibre of God
>>64563724>explainI already did, read the rest of my post.
>>64564092Obviously, the initial guy's wrong, since there are plenty of hotter loads around that case head size, but when could it actually be an issue?
>>64563724NTA.Bolt thrust = Max chamber pressure * the max internal area of the case. This is the force applied to the bolt and locking components. The gas pressure pushes in all directions, including backwards towards the bolt. The more bolt thrust there is, the beefier the locking components must be to withstand it all. It’s why overpressure ammo breaks bolts.So you’ll notice that since 5.56 and 6mm ARC (or anything based on the 7.62x39 case) must both chamber in an AR15, thus using bolts of the same size/strength, the pressure of the 6ARC must be lowered, because the base is so much wider. If you loaded it to 60kpsi, the bolt thrust would be enormous. Same with any other large case AR15 cartridge. 458 socom, 50 Beowulf, 400 legend, etc. they’re all like sub 40kpsi.It’s worth noting that the AR bolt isn’t as weak as it seems. POF uses ar15 sized bolts made of some fancy metallurgical alchemy called “aermet” in the Revolution rifle. This withstands the bolt thrust of a 308 - fucking insane.
>>64564178>hotter loads around that case head size…feeding into actions with larger and stronger locking components. That, or the bolt is made of some super alloy. There is a high pressure loading of 6 ARC suitable only in bolt guns with much stronger locking lugs than the AR15
>>64564178It's never an issue, you just have to design your bolt strong enough to handle it. You'll have issues if you machine out a smaller bolt, like one designed for 5.56, to fit a larger case head, like 5.45, and then you'll have more bolt thrust and less metal to take the load. If you start with a cartridge and then design a gun for it, you'll use a properly designed bolt and then you won't have issues even with 14.5x114.
>>64564934>…feeding into actions with larger and stronger locking components.No action was specified. I guess a proto-G3 was mentioned, but the G3 isn't exactly fragile, is it?
>>64564922Informative, anon. Big thank.
>>64566482>I guess a proto-G3 was mentioned, but the G3 isn't exactly fragile, is it?A proto-AK would be possible too.But it would also be gay.
>>64564922>since 5.56 and 6mm ARC (or anything based on the 7.62x39 case) must both chamber in an AR15, thus using bolts of the same size/strengthThey're not the same strength, that's the point. See pic related, the right is what happens when you mill out an AR bolt to fit an x39 bolt face.
>>64566516Yeah I left that out. The weaker bolt is not the principle reason for the reduction in pressure of x39-based cartridges. But it does contribute.
>>64566548The weaker bolt in modified AR-15s is exactly the reason why 6mm ARC factory loadings are lower pressure, because it was marketed as an AR-15 cartridge and that bolt is paper thin and unsafe for full pressure loads.The size of the AR-15 bolt is not the reason why 7.62x39 loads are low pressure, since it's designed for the SKS and AK, which have bolts large enough to safely accommodate the x39 bolt face. 7.62x39 loads are relatively light in order to control recoil and give headroom for shoddy Soviet QC.
>>64563747Post last Impala you shot w/6mmarc at 800yrds.
>>64563737
>>64567162How does it perform at a mile though?
>>64567268>mileWhy use small arms?
>>64567275GPMG.
>>64567281machine guns exist chambered in 6.5×55>1 mileget a .338
>>64567340Anon, you're a stupid cunt.>>64547888>Would the 6mm ARC have been the best universal cartridge (rifle, LMG, HMG) for WWII?
>>64567777wasted and (You) are a Dumb Fuck brainlet plebbitard that doesn't belong here, go back
>>64567884I've been on this site for about 20 years.Read the OP before you reply, nigger.
>>64567900checked, Shut The Fuck Up and Get Out Of Here, now
>>64567900>I've been on this site for about 20 years.This can't be a good thing.>Read the OP before you reply, nigger.Confirmed. Protip, you would get your ass kicked for acting like that irl, cyberfaggot.
>>64567962>>64568026https://www.youtube.com/watch?v=gjBFc5L6E1g
>>64547888The 6mm ARC has great ballistics but suffers from other limitations such as poor feeding, poor magazines, and brittle bolts. 5.56 was made great by tens of millions of rounds being fed through M4s. If 6mm ARC had that level of continuous usage and improvement, yeah, maybe it would be wonderful. As it is now, we can't even get a magazine for it that feeds well.
>>64547888The concept of a universal cartridge is flawed. You need to cover the range from pistol to heavy machinegun. You can't do that with a single cartridge. Right now it's done with four main cartridges (9mm, 5.56, 7.62, .50). If you want to do it with three, you're better off either combining 7.62 and .50 with something like a .338 magnum, or 9mm and 5.56 with something like .20 VarTarg or the LSAT 5.56 CT. Hell, imagine a paradigm where we do both and field a pistol, smg/pdw, carbine, and LMG all chambered in a 5.56 CT cartridge that's small enough to fit in a grip mag and straight walled to fit in a P90-style magazine depending on the application, and a DMR, MMG/GPMG, and HMG all chambered for a .338 CT cartridge with double the effective range of 7.62 NATO.
>>64568652Regarding a universal cartridge for pistols, SMGs, and rifles, is there even a point to it if the magazines aren’t interchangeable? Cause in practice, a p90’s loaded mag can not feed into a pistol, so it is of no consequence to me that they chamber the same cartridge. I understand it’s simpler from a logistics perspective, but the value is kinda diminished if each gun takes a different mag.>20 VarTargBased knower-of-what-this-isI wonder if you can’t just obsolete the pistol by making a mag-in-grip assault rifle, maybe with like an 8” barrel, that’s small enough to holster, chambered in something high pressure but with a moderate overbore ratio, maybe 221 fireball or 6x35 TSWG. What’s anyone doing with a pistol anyways?
>>64568652I spent the last two weekends crunching numbers for my dream intermediate cartridge load in a polymer telescoped case, a sort of Creedmoorization of 5.56/5.45 and based on .204 VarTarg load data.>projectileHornady .224 90gr A-Tip, OAL ~= 1.24", i7 FF=0.87, SD=0.256 G7BC=.295. Twist rate: 1:6.5scaled down to .183 (4.65mm), steel tip FMJ, ignoring Reynolds number and similar, scaling factor = 0.817.183, 50-gr, OAL=1", i7 FF=0.87, SD=0.213, G7BC=0.244 (!!!). Twist rate: 1:5Equivalent copper solid: 42 grains, SD=0.180, BC=.200. Higher BC than 77gr SMK at almost half the weight, but may require a faster twist. Either way, 1:5 isn't too bad.Run at that 3000 fps, that's a 1000 foot-pounds for the 50 gr. 3200 fps for the 40 grain, 1137 fpe, with *HALF* the recoil of an inferior 77 gr SMK.>case1.56" long, 0.350" diameter case. Incredibly small, with more mag capacity than 5.56/221 Fireball, and somehow still shorter than 5.7x28. I might actually stretch it to 1.6", same as 5.7, just to give it more internal volume. Boxer small rifle primer, 0.025" thick walls, 0.12" thick base.I modeled this in SolidWorks and arrived at an approximate usable (i.e. excluding the long bullet and endcap) internal volume of 0.05 cubic inches, or 12.6 water grains. This is too close for comfort and future development, but should actually be enough for the 40-gr copper solid load at least, as 39gr .20 VarTarg only requires about 13 grains of propellant for 3000 fps+.St. Marks found that CT compressed loads may be densified by 20-40% over bulk volume and require 10% less propellant for the same performance. They achieved M855 spec with 23.4 grains of their powder, and M855/M855A1 is typically loaded with 26.1 grains. https://ndia.dtic.mil/wp-content/uploads/2012/armaments/Wednesday13627drummond.pdfAssuming 40% densification (1400 kg/m3), we can fit around 18 grains of a ball/pellet powder with a bulk density of 1000 kg/m3. If actually achievable, this is excellent.
>>64569599Oh, and weight: >M85512 grams total = 185 grains62gr bullet+26.1 grain propellant+ 93 grain case + 4 grain primer>4.65mmCT, 42 gr copper solid5.8 grams total = 90 grains42gr bullet + 18gr* propellant + 15 grain case (0.042 in3 Ultem) + 10 grain cap (0.027 in3 polycarbonate) + 5 grain primer/cup*best case scenario; either way, stretching the case won't significantly increase its weightApproximately half the mass of M855, with lower recoil and vastly superior ballistics. Not to toot my own horn, but it doesn't get much better than this.
>>64569599>90gr Hornady a-tip .224The form factor of 0.87 is high for the ~5.5:1 L;D. Picrel is the .510 750gr A-max. L:D=5, i7ff=0.79. You can maybe improve it a bit by shortening the bearing surface by ~0.2 calibers or so.One more thing. What do you gain from going CT vs conventional? CT cartridges don’t play well with long ogives, so what you gain by “telescoping” the bullet and propellant is minimal compared to a conventional case. The polymer case walls look really thick too, encroaching on the already diminutive case capacity. Brass or steel case would give much greater internal capacity for the same base diameter.
>>64569599>>64569672>>64569692(me)Forgot to add:The 90gr a-tip has a bearing surface that’s like 2.5 calibers long. There’s easily a whole caliber there that could just be omitted without degrading the form factor. Or just added to the ogive and boat tail.Here’s a useful resource for calculating bullet weight and estimating BC/FF. I modeled a 5 cal long bullet with 10mm diameter (so every caliber = 10mm, easy to scale this way).http://www.geoffrey-kolbe.com/cgi-bin/drag_working.cgi?unit_length=mm.&weight_unit=grains&bullet_name=Custom+bullet&re_calculate=yes&boundary_layer=L%2FT&diameter=10&length=50&nose=29&meplat=1&drive_band=10&base_diameter=8.15&angle=7.5&boat_tail=7&secant_radius=19&weight=335.7&density=11Leave the base diameter field empty when you’re adjusting boat tail angle/length.
>>64568652>The concept of a universal cartridge is flawed.You lack vision, homo.
>>64568652>You need to cover the range from pistol to heavy machinegun>pistolNo, you don't.
>>64569672unironically you should make one of these and enter a govt competition, like the guys at Accuracy International did after making a prototype L96 at home and winning the big govt contract
>>64569692I actually considered the Berger .375 379 grain ELR match solid, which had an FF=0.79 but a L:D=6. Yours is a much nicer bullet. I ended up choosing the 90gr with its relatively high FF to reduce the potential of Reynolds number problems that come with scaling and because military bullets can't always have the lowest FF possible, but I might change it yet.>What do you gain from going CT vs conventional? Honestly I just like the technology. In this case, I mostly picked it for COAL and weight. It has other advantages like being able to load bullets with different length ogives (or zany stuff like multiple projectiles) more easy and being designed for use with compressed loads, which seem to be better, and I'm a big fan of the operating mechanisms used by CT guns. It is true that conventional cases are better for longer ogives, but I don't think it's that influential at the scales we're dealing with.Here I sketched a .218 Bee-ish taperless case necked down to .183 for the 4.65mm caliber, with an internal capacity of 20 water grains. Its diameter is almost identical to the CT at .349". After inserting the 1.015" bullet to just shy of the ogive, it has a usable capacity of 0.063 cubic inches, but keep in mind that the powder can't be compressed to the same extent in a conventional cartridge. This just serves to demonstrate the COAL difference, which isn't all that significant in this case. The ".183-218" would likely weigh around 8.5 grams, 7.5 grams if steel or polymer case.
>>64569703>The 90gr a-tip has a bearing surface that’s like 2.5 calibers long. There’s easily a whole caliber there that could just be omitted without degrading the form factor. Or just added to the ogive and boat tail.Yeah, the illustration on Hornady's website doesn't look too bad but the bearing surface is actually scarily long when you look at it closely. It's not completely useless, though, since mass and therefore SD comes at a premium in this caliber range. The length is still better invested in the ogive obviously. Maybe a hybrid >Here’s a useful resource for calculating bullet weight and estimating BC/FFThis website is fantastic and surprisingly accurate. I actually found it a short time ago, don't know where or exactly when. And your bullet is neat too, around 0.85 FF.>>64569731It would infringe on several dozen patents, unfortunately. A steel/polymer-cased .20 VarTarg is more feasible, maybe necked down to .17, .183 or a similar caliber.>>64568652Jim Schatz actually wanted to merge the zones between 5.56 - 7.62 - .50 with 6.5 and .338. I don't think it's possible to completely abandon the .50 cal, and while I think a cartridge with similar weight and recoil as 5.56 but with much longer legs would be cool (ESPECIALLY for M240 gunners, ooh mama), I think warfare has evolved such that the individual soldiers' small arm is more like an augment to the other weapon systems employed by his element. I wholeheartedly agree with the Uzi-sized assault rifle concept. It would be awesome if soldiers could keep in a holster a magnum PDW system that allows them to comfortably engage targets at 500 yards, but is small and lightweight enough they can more comfortably utilize and carry other weapon systems, most saliently drones. That's what I was aiming for with my 4.65mm cartridge.
>>64570009I’m the first guy you responded to, but this is regarding your last paragraph, mag-in-grip assault rifles. Picrel. If you made the grip out of steel, wire EDM’ed the magwell, then machined the exterior, the black part of picrel would be the cross section of the grip at its smallest point - where it interfaces the web of your hand. Off the top of my head, the grip is ~25mm wide and 55mm deep. You would of course add a palm swell and maybe some finger grooves for structural support to the extremely thin front strap. The front strap is 1mm thin, the sides are 1.5mm, and 0.8mm mag walls. anyways, all this allows a cartridge with an OAL of 1.85” and base diameter of 11.2mm (6.5 grendel case) to be fed through the grip, double stacked. In my pic, that’s a .284, but I fucked around with the powley computer and found that a 30 cal works better. At 80kpsi, the 110gr v-max bullets (G1=0.29) should go about 2500fps (9” barrel), for about 1600ft*lbs at the muzzle, and retaining 700+ ft*lbs at 300 yards.> “but the grip would be too big”I tore apart one of my vapes a while ago and it just so happens that one of the internal components is exactly the size and (almost exactly) the shape of the grip I sketched up. It’s not even close to “too big”. you can probably add like 3mm to the depth and width before it starts to feel a bit uncomfortable. And my hands are just normal size.
>>64569111The benefit of fielding a unified cartridge are in the cartridge, not the magazines. But yes, there's no reason why you couldn't design an AR to take Glock mags, for example.>>64569712>>64569728What sort of retardation is this? Does "vision" let you stop fielding entire categories of weapons without losing capabilities?>>64570009Merging 5.56 and 7.62 is stupid, because 5.56 weapons use 5.56 for its capacity and 7.62 weapons need more range and power. A "universal" cartridge reduces the capacity of 5.56 weapons and the power of 7.62 weapons; it's the worst of both worlds. A .20VT and .338NM paradigm results in fewer cartridges to manage than a 9mm, 6.5 LICC, .338NM arrangement, which reduces capacity of your carbines and LMGs (it uses the .308 bolt face), and gives you the choice between decreased range and lethality compared to .308, or moving your MMGs and DMRs to .338 and not actually unifying anything.
>>64570125Sorry if I sounded like it, but I don't think this concept is impossible with conventional cartridges at all. The Aimpoint PC-80 had a magazine in the grip and was chambered in the 1.83" .221 Fireball, and was fairly comfortable despite having a normal stamped magazine and a relatively thick rubber layer on the grip. Your design is likely very comfortable, but may be a little expensive. I don't think slightly thicker pistol grips would be hard to get used to for most guys.As for the cartridge itself, I personally prefer the lightweight microcaliber idea, like .20 VarTarg or .17 Mach IV (both necked-down .221 Fireball cases), because it lends itself well to higher SDs/BCs with less recoil, but the mini-Blackout/7.5 FK Magnum approach is awesome too and may be more realistic and closer to the industry state of the art. I love your design. Have you written about it in more detail somewhere?
>>64569599Why not the Steyr ACR's annular primer? The fixed firing pin seems like an easy way to simplify a lot of stuff if you're going to do a CT rising chamber.
>>64570206> I love your design“Design” is really an overstatement. More like “something i sketched up”, lol. But no, I haven’t written anywhere. I pretty much just post here.>aimpoint PC-80Wild that i am only just now learning of the existence of this gun. I just got done watching Ian’s video on it from some months ago. I’m surprised how short the receiver is. Look how much further back the receiver of the mp7 extends relative to the grip. The PC-80 is tiny. Zero reason we can’t have holsterable assault rifles.By the way, speaking of micro caliber cartridges, have you heard of the calhoon 19s? Check out the “19 calhoon Badger”. There’s very little info available online - it is really obscure - but it’s a 30 carbine necked down to 197. It would make for a great mag-in-grip chambering.
>>64570197I think you should consider what each class of ammunition brings to the table. >5.56A lightweight, low recoiling cartridge for individual weapons and the SAW. Excels at close combat and personal/squad-level fire and maneuver. >7.62A general purpose cartridge that is currently used for DMRs and what is perhaps the most important small arms category in most doctrines, the general purpose machine gun.>.50 BMGAn echelon weapon cartridge whose main advantage is the ability to load chemical effect rounds, like the "silver-tip" M8 API.>9mm Not really used by the military, and when it is used, it's usually special order.Jim Schatz's main goal was "bridging the gap" between 7.62 and 5.56 with .264 LICC (the idea that the IWTSD LICC is based on), which is actually much closer to 7.62 or 6.5 Creedmoor than 5.56 in power. I think he wanted the power of the GPMG further down than what's currently employed by the Army, which is M240Bs at the platoon level, and the close combat people can eat dirt because their job doesn't matter. It actually isn't too bad of an idea, provided that the cartridge is light enough. 20% heavier than 5.56 (AKA 40% lighter than 7.62) with Creedmoor performance is a very good deal for machine gunners and DMs, while remaining tolerable for riflemen. Now that I think about it, it's actually pretty similar to many WWII MG-centric doctrines. Your paradigm weakens the 5.56-equivalent cartridge, which isn't a problem IMO, but introduces issues with the other two categories. .338 Norma Magnum is almost twice the weight of .308, that's almost half the magazine depth for machine gunners, who are the biggest consumers of ammo. .338 is also not big enough for chemical effect bullets, so it can't really replace the .50 cal, a cartridge for which ammo weight is not a concern.>>64570692The Steyr ACR only did that because it fired exclusively from an open bolt to facilitate burst-firing. This is generally considered retarded now.
>>64571008>have you heard of the calhoon 19s?I haven't, these are great. Everyone seems to report very good performance. James seems like a cool guy too. The .19 Badger looks great. 1.3" case, about a tenth of an inch shorter than .20VT, and 3550 fps with the 32gr .197 bullet.
>>64570197>What sort of retardation is this? Does "vision" let you stop fielding entire categories of weapons without losing capabilities?When it's a pistol? Yes.Pistols have become obsolete and are only around due to institutional inertia nowadays. Every member of the military using pistols would be better off with an SBR in 5.56.
>>64569692>What do you gain from going CT vs conventional?according to the patents: >shorter length (pack more in less space)>higher pressures due to fully supported case>if using a moving chamber mechanism: less barrel heat, ability to skip having an ejector and extractor (less mechanical complexity)>lighter weight by about 40%>clean sheet design means it's easier to sell current generation bullet geometries instead of carrying 1950s designs with bad aerodynamics
>>64566516I spent ages looking for something like this, didn't know the search keywords so I gave up. And of course it's CMMG. It's a shame it can't be done with standard uppers.>>64571780CT is pretty neat for internal ballistics too. In addition to getting compressed loads by default, the freebore is massive without significantly worsening accuracy, so you get a shallower pressure curve and more performance with lower max pressures. AFAICT, this may be why CT cases require 10% less powder at the same peak pressures. Long freebore isn't peculiar to CT obviously, you can just design a chamber with a long leade. But you can also cut off the case neck, which also has the effect of giving you more capacity for a given case length. picrel isn't just about the case material.
>>64571780>if using a moving chamber mechanism(btw textron patented a design with a normal chamber too, though they never built it)https://patentimages.storage.googleapis.com/5c/f3/ee/641e8f18c7b702/US10619954.pdf
30-06 won 2 worldwars and would win 2 more if they'd let it.
>>64547888I like intermediate cartridges, but WWII cartridges were pretty much perfect for their machine gun doctrine. It's a lot like accepting that line infantry was the best way of fighting back in the black powder era.
>>64573967You're forgetting the synergy effects of having assault rifles. The main advantage is mobility, which is also conferred to your MG.Pic related.
>>64574087
>>64574087I remember that thread. That post is totally worthy to be immortalized in the form of a screenshot,
>>64574087>The main advantage is mobility, which is also conferred to your MG.Oh yeah, absolutely. A platoon with only machine guns and several MGs is definitely fucked if guys with assault rifles snuck up on them. But if you're artificially restricted to one cartridge for frontline enlisted, as the Germans were, then it makes sense, especially since this doctrine was developed in WWI when reliable autoloading weapons were still an order of magnitude more expensive than bolt-action rifles. The moment autoloading rifles become cheap enough, and if you're still intent on only using a single cartridge, you can comfortably switch to a lighter recoiling cartridge that you can still use for indirect fire like 276 Pedersen or a hotter 280 British. 7.62x51mm was picked for the same reason, but it's a little too big, making the logistical advantage not worth the recoil and weight penalty. The advent of high BC bullets simplifies this equation significantly.
>A platoon with only machine guns and several MGsa platoon with only a handful of machine guns and bolt-actions for everyone else*
>>64574327>Oh yeah, absolutely. A platoon with only machine guns and several MGs is definitely fucked if guys with assault rifles snuck up on themIt's less about sneaking and more about fluidity and tactical mobility. To quote a German veteran "we didn't have to stop anymore." I think it's explained further in the posted pics.Doesn't seem like a big deal in an era where everybody is used to assault rifles, but it really is, both on the offense and defense.>when reliable autoloading weapons were still an order of magnitude more expensive than bolt-action riflesOne shouldn't forget that auto-loaders become much easier to design and produce reliably with a less powerful cartridge. It's why the Stg44 was able to go BRRRRRRRR so reliably with minimal effort while the G43 didn't.
>>64571185MMGs are almost always going to be emplaced or vehicle mounted, so they don't have such strict weight requirements as individual weapons, and for the same reason, they also don't have to worry about recoil. Additionally, the weight increase can be mitigated by switching to polymer case ammo, which is already in common use for .338 and .50. With this setup, MMGs will have range and stopping power approaching that approaches that of HMGs, while HMGs won't give up that much in the way of downrange energy due to higher BC projectiles while gaining substantially more ammo. The total weight of ammo in theater wouldn't be so much increased as reallocated.Meanwhile, the M249s would be gaining a substantial amount of ammo given their restriction of needing it all to be carried by one, maybe two guys.
>>64574615>It's less about sneaking and more about fluidity and tactical mobility. To quote a German veteran "we didn't have to stop anymore." I think it's explained further in the posted pics.I read it, it's a great post. I understand and agree, just couldn't acknowledge it concisely. Maneuver is certainly the infantryman's primary tool, the weapon just allows that. I've argued in like a dozen threads that the soldier gets paid to walk up behind the enemy, not to shoot at them, mainly to highlight the importance of lighter equipment and to denounce battle rifles.>One shouldn't forget that auto-loaders become much easier to design and produce reliably with a less powerful cartridgeYep, same for the Pedersen rifle.
>>64574691>and to denounce battle rifles.
>>64574754Yes.
>>64574754Battle rifles are just inferior assault rifles. There's no reason for full auto with a full power cartridge. Machine guns excluded, of course.
>>64563747Shooting game at half a mile with any variety of ammunition is fucking retarded. They’re animals, not hadjis
>>64576614Manlet detected.And literally just add a bipod.Voila, you got an LMG.
>>64577609>Give everyone in the squad MGs>Now you've lost the ability to maneuver, which is the one thing they were supposed to do
>>64577611>Battle rifles make it impossible for you to maneuver1. Look up Rhodie tactics2. I was joking about the manlet thing before, but you're literally girl-sized, aren't you?
>>64576626What if it's the most dangerous game?
>>64577609And chamber it in 5.56 and you get something you can actually fire in full auto without burning through all your ammo in two minutes flat while also actually hitting your target.
>>64577617Rhodesia would have been better served by L85s than their FALs.
>>64573731>freebore is massive without significantly worsening accuracyYou got a source for that? I seem to recall LSAT and Textron had issues aligning the chamber with the barrel. I'm also not convinced ramming a bullet after so much freebore wouldn't wear the throat prematurely, or affect the jacket engraving. Copper is soft, and engaging the lands at a much higher speeds sounds harsher than what would happen with normal freebore.
>>64580241The only source for that is one anon on 4chan with no inside information claiming it must be the reason Textron dropped out of the competition. That anon instantly begins coping and seething when it's pointed out that General Dynamics dropped out at almost the same time.
>>64580241The Weatherby cartridges have a freebore sometimes half an inch long and don't have throat erosion problems other than what's expected for similarly overbore cartridges. Mechanical wear is one of the least impactful factors in throat erosion. Heat flux is by far the main direct contributing factor, followed probably by the chemical reactivity of the powder, and only then everything else, like pressure and mechanical wear from different jacket materials (as long as it isn't, like, aluminum or tungsten), but they all work in tandem. You can't easily isolate every element of the combustion process, e.g. hotter gas fronts are usually higher pressure, but heat as measured by overbore is the best predictor even with long freebore.
>>64579766> while also actually hitting your target.*at low range and without the possibility to penetrate armor worth speaking of
>>64573731>AFAICT, this may be why CT cases require 10% less powder at the same peak pressures.Now that's interesting. I specifically remember Kori Philipps, LSAT's program supervisor, mentioning that CT always requires 30% more powder to get the same velocities as conventional in her interview with Nathaniel F. on TFB, even with the powder sitting entirely behind the ogive. That's not contradictory per se, but it seems counter intuitive.
>>64581582Tungsten 5.56 and tungsten 6.8 have the same penetration.Same for normal ammo.You aren't going through plates.
>>64581886True, that's why all MGs use 5.56.
>>64581840You're referencing this article,https://www.thefirearmblog.com/blog/2015/05/21/textrons-lsat-program-unveils-7-62mm-plastic-cased-machine-gun-mockup/where Nathaniel cites a 1996 report by the Office of the Inspector General regarding some large-caliber CT efforts that were active at the time. The report was not entirely accurate; see attached for the great Anthony G. Williams' comments on it in his book "Autocannon." Nathaniel Fitch himself was rather skeptical of CT in 2015, he only came around to it in late 2016 and seemed to support the concept after his interview with Kori in 2017.Here's the report itself.https://media.defense.gov/1996/Jun/14/2001715295/-1/-1/1/96-164.pdfMy opinion: in the first table (page 16 of the PDF), you can see that the ARES .50 cal achieves rough parity with conventional for propellant efficiency, while the others do indeed suffer from the problems mentioned in the report, even when accounting for the very "experimental" muzzle velocities. Modern small arms CT uses the ARES/Stoner design.Phillips addressed the barrel wear question in the interview the same way:>TFB: Other caseless and cased telescoped programs – like the Air Force’s 25mm GAU-7 that was originally intended for the F-15 – have had problems with barrel wear, specifically in the throat area. Can you tell me whether LSAT ever had those issues, and if so how they were corrected?>KP: One of the problems with some of these previous programs was that they promised other things in addition to lighter ammunition – more range, more power, etc. In the case of the 25 and 30mm telescoped ammunition, they were using a lot of propellant and very high chamber pressures, which really exacerbated issues with wear. This was one of the reasons we only promised lighter ammunition in the beginning. We wanted to work on the technology itself.
6 ARC is ultimately still a cartridge that compromises itself to fit in an AR15 platform. We know it does not stack well in magazines, that the bolt head needs to be thinned, etc. What we need is to design a 6mm round to be ideal, then build a gun around it. Like the NGSW program, but not for a shit round.
>>64582087Just make it skinnier and don't use an AR.
>>64580260I know the story. The source was a deleted video of a guy working on suppressors for Lonestar, he let slip that Textron had dropped out while doing a Q and A. He said nothing about his own company dropping out. Lonestar stayed in until the end and were dropping marketing videos for their bullpup mere weeks before the winner was announced. Are you that conspiracy theory guy? I vaguely remember someone with your opinions making crazy assertions based on conjecture, rather than anything solid.
>>64582107>guy working on suppressors for Lonestar, he let slip that Textron had dropped out while doing a Q and A.It was Joe Hajny the LMT sales rep that let it slipped in a Q&A on their youtube channel. Textron was using a LMT suppressor for their rifle submission.
>>64582090Indeed. The 9.6mm diameter of the .223 case really lends itself well to magazine capacity.Just make it longer, add a long skinny low drag 6mm bullet and you're golden.
>>64582107>Lonestar stayed in until the endWithout GD, who dropped out at the same time Textron did. Conveniently, both of the big prime contractors left at the same time, when contract terms and right to repair was a big deal for Congress looking at military procurements (ultimately the M10 Booker, also made by GD, was canceled for this very thing after billions were spent on R&D and tooling up for volume production and dozens were already being delivered. Textron's Scorpion light attack aircraft lost a bid for the same reason a few years earlier.) and IP licensing terms were specifically called out in the original RFP for the NGSW as being a particular area of concern.It stands to reason that what happened was that the Army decided that none of the prototypes was so much better than the others that it was worth the added lifetime cost and risk of losing the project's funding over bad contract terms, and they wanted to actually buy their guns. Textron and GD weren't interested in selling guns since both companies make most of their profits from essentially leasing hardware to the military, and making sure they're the ones who get paid any time something breaks and needs to be fixed.True Velocity stayed in because obviously their company has no chance of staying in business if they can't come up with a government contract before their investment money runs out; no one is buying plastic 5.56 for 300cpr. They bought out GD's share of the partnership and went back to the Army with better terms so the competition went on with two competitors and no big MIC prime contractors.
>>64581582>>64581888You're retarded
>>64582689What do you mean? Isn't 5.56 the standard caliber for all MGs?
>>64564934>>64564945>>64566501>>64566516>>64566548>>64566877That problems been solved for over a decade
>>64584080The problem has been solved since about 1947.
>>64548054>>64548234Yep. 6.5 Grendel is the perfect "Do everything good, nothing bad" cartridge.As far as capacity goes, 5.56 is excellent, either run it forever or don't. But 6.5 Grendel is is usable for everything from infantryman, to general purpose machine gunner. Everything but dedicated long range sniper rifles. Otherwise, use a fucking explosive.
>>64584502>6.5 GrendelDoesn't it have low velocity and thus low range? Seems like 6 ARC is better.
>>64584557wrong. it maintains more lethal energy at 1000 yards than .308
>>64584580>1000 yards
>>64584580So does a cannonball. But what about the bullet drop? The trajectory?
>>64584585It starts having more energy than fast 130gr .308 around the 400-500 yard mark. It has the perfect amount of energy vs. recoil at close combat ranges and retains enough even for stuff like indirect fire. It's an awesome round balistically, and legitimately a realistic .308 replacement, which says more about .308 than it does about 6.5G honestly.>>64584629Even slow Grendel is known to have an almost identical trajectory to .308 out to 500 yards. No shade, but how old are you? This stuff is borderline common knowledge.
>>64576614>Battle rifles are just inferior assault rifles.Battle rifles are superior to obese SMG tier assault rifles that are Stg-44 and AK.>There's no reason for full autoFtfy, assault faggot. Machine guns excluded, of course.
>It's another episode of anons wanking to VLD bullets and pretending they are ballistic geniuses while every military in the world is a bunch of know nothing retards.
>>64585038It does not take an intellectual to ascertain that virtually all militaries make stupid procurement decisions. Their choices are subject to outdated or delusional doctrine, budget constraints, corruption, arbitrary requirements, and deafness to soldier feedback.We all know the ideal assault rifle would be and electronically fired, downward or forward eject bullpup that uses 6.5mm polymer cased ammo and feeds from quadstack magazines. But here we are.
>>64584580>rainbow trajectorylmao
>>64585081you do not hate Gen. Overmatch enough
>>64584580>wrong. it maintains more lethal energy at 1000 yards than .308HMGs are gonna have to go at least twice that far, anon.
>>64584557NTASort of, but the BCs are real good, so as the range increases, the average velocity stays higher than you’d expect. 6ARC does infact have better external ballistics. Better BCs by virtue of a finer bullet, and faster velocity.>>64584580Eh, idk about that. 6.5 grendel starts off with about a 1000ft*lb deficit, and its BC advantage over 308 - if it even has one - is very slight, it’s not gonna make up for 1000ft*lbs over 1000yards. Trajectory wise, IIRC 308 is a bit better. It will propel bullets of equal BC to higher velocities.But 6.5 grendel does fit in an AR and punches above its weight class, so there’s that.
>>64585318It would be perfect if it were designed for a custom bolt. It's seriously cucked by the low pressure, it's much worse than the COAL restriction.
>>64585038Exactly. To be completely fair though, the Swiss had a damn good match bullet going back the the teens. In theory the technology was there. Was people are really missing is that the expanding tipped bullets and copper expanding rounds that exist today, and make small calibers viable at extended ranges, weren't possible back then. There's a reason why militaries adopted basically the same calibers in unison going all the way back to the .60s muskets.
>>64585038>>64585081Goddamn Russia made the 5.45 7N22 with a G7 form factor of 0.935 in the late 90s, and it's not even supposed to be a long range load. It's not hard at all, the West is just obsessed with short ogive bullets for some reason. Form factor isn't even a familiar term among traditional shooters (and I daresay fucking government ballisticians, including the ones who designed 6.8 SPC), who seem to prefer measuring bullet performance with "weight," which is a confusing term that conflates length-related form factor reductions with sectional density.
>>64589557> including the ones who designed 6.8 SPCYou know they tested a 6.5 and a 7mm SPC as well? Meaning, the conclusions such tests would draw were mysterious to these “ballisticians”, thus experimentation was warranted, so they wildcatted 3 different calibers, made barrels, and test fired them. The results were not surprising. The 6.5 had the best external ballistics and penetration (duh), and the 7mm had the best terminal performance (also duh). But this all came as a surprise to them.. They split the difference with 6.8SPC, with like a sub 2 caliber ogive. Just a huge clusterfuck. And these guys are in charge of weapons developement for the army?If we lived in an alternate reality where these ballisticians were aware of something called the atmosphere, and instead they made a 6 or 6.5 SPC with a 3 caliber ogive, there’s a chance that would be the standard service rifle cartridge today. And nowadays we’d be playing around with 80kpsi loads for it.
>>64589592GWOT and the obsession with terminal ballistics that it created have been a disaster for the science of ballistics, and we're still feeling some of its effects to this day (the NGSW's armor penetration is also a useless meme). I would have said that the Army Marksmanship Unit should be axed like the Ordnance Board, but they also created .264 USA, which isn't particularly impressive being a less powerful 6.5CM, but isn't a complete dumpster fire either. They're treading on thin ice.>If we lived in an alternate reality where these ballisticians were aware of something called the atmosphere, and instead they made a 6 or 6.5 SPC with a 3 caliber ogive, there’s a chance that would be the standard service rifle cartridge today. And nowadays we’d be playing around with 80kpsi loads for it.I'm very hopeful for the LICC program, whose cartridge is essentially a shortened and higher pressure .264 USA. I'm not a big fan of these "magnum intermediate" cartridges, but it's a step in the right direction for bullet design/selection.
>>64589640>GWOT and the obsession with terminal ballistics that it createdI've been seeing this meme start to pop up a lot among people who were too old (or too young) to be in GWOT. It's wrong. It goes: we need to fix X problem caused by GWOT - where X is something which had nothing to do with GWOT.GWOT did not cause NTC rehearsals - nobody had time for rehearsals, the very concept was mocked mercilessly.GWOT did not start modern ammo autism - the late 1990s-early 2000s growth of internet forums did.GWOT did not cause an outcry for big bullets - that was cope coming from the boomers who weren't there trying to fortify their 1980s battle rifle narratives against the reports from actual soldiers giving glowing reviews of 556 green tip.
Actually, after giving it more thought, the AMU doesn't deserve all that criticism. Everybody was retarded and incompetent back then, I myself used to think .223 was a puny varmint round. And the AMU had nothing to do with the NGSW and its ridiculous energy requirement to my knowledge.
>>64589672And by "everybody" I only mean the mainstream narrative and most laymen. A lot of the criticism and evidence that I use against full-power rounds now comes from people who were championing 5.56 and other SCHV cartridges since the turn of the millennium and earlier.>>64589667All true, and I was indeed too young for most of GWOT (born in 2000). I guess GWOT just fortified existing power/caliber retardation, like how armor penetration was used to push NGSW.
>>64589695>All true, and I was indeed too young for most of GWOTThen how do you know it's true?
>>64589707I don't know anon, how do you know about WWII? I was iffy about GWOT causing terminal ballistics autism anyway, and I only noticed that the supposed terminal performance benefits of full-power rounds are currently only being pushed through by wrinkly generals after that anon (you?) pointed it out.A modified, more holistic perspective includes the view that GWOT and other long-term low-intensity conflict promoted a dysgenic hyperfocus on (often) irrelevant bullshit, or at least stuff that wouldn't help in a hot war. In other weapon systems it's often shit like reduced collateral damage - in small arms it manifested as an obsession with terminal effect on drugged-out Islamists, which is similar to the handgun 'stopping power' debate that raged on in contemporary internet forums. It's not that external ballistics were shunned or that there was no progress; development continued, just not on the things we tend to value more today. Reduced collateral damage munitions ended up being a net positive in the end, green ammo is pretty cool.
>>64589592>You know they tested a 6.5 and a 7mm SPC as well? Meaning, the conclusions such tests would draw were mysterious to these “ballisticians”>>64589640>GWOT and the obsession with terminal ballisticsThey were retardsOne of (if not the) main guy behind the 6.8 SPC was Sgt Steve Holland. He's often a guest on the Tactical Rifleman youtube channel.They did a special livestream some years ago specifically about how the 6.8 SPC was created (video since deleted, or at least can't find it now). It was so retarted i couldn't believe it. The guy was mocking people "talking about BC", "crushing numbers"... and that what matters is what "kills people". And what kills people? Making a hole inside them so they bleed and they shut down (compared it to hydraulic leak or something like that). And what is the most effective cartridge for that? Well, obviously, the 7.62x39 soviet ak round... That's what his model was for an ideal cartridge and for the 6.8 SPC. The paramount of all cartridges, the fucking 7.62x39.Tha's how retarded they were.
>>64589766>I don't know anon, how do you know about WWII?Mostly from reading about it in good sources. That's why I asked you.
Another fun one is that the reason the NGSW uses a 6.8mm bullet is because the Army conducted a study that concluded that the ideal range of calibers for small arms is 6.8mm +/- 0.8mm (meaning between 6mm and 7.6mm). Someone read that study and decided it meant 6.8mm is the deadliest possible bullet diameter, and the rest is history.
>>64590025I knew from the moment of 6.8 SPC hype two decades ago it was all total bullshit6.5 Grendel was always the king, until FN IWS 264 came along
>>64585964Rumor has it that Rexus bolt can handle full pressure loads without failing, so you could probably get away with pushing 60k PSI with the right parts. Perhaps with newer steel cases pushing 80k PSI now there will be a push for an enhanced AR-15 upper/barrel/bcg spec that solves the pressure issues wholesale while still dropping into a standard lower and we can start getting 6.5 CM ballistics out of a Peak alloy or Shellshock Grendel (with much shorter barrels).
Why has nobody taken advantage of the ar-10 magwell to just make spicy longboi 6mm rounds? 30rds per mag is a worthy benefit.
>>64592724Reduces powder burn efficiency which costs you velocity for the same quantity of powder. Modern PRS autism cartridges are all short and fat for this reason. The closer to a sphere the casing is the more efficiently the propellant burns.
>>64592724Because AR-10 mags are designed to fit .308 size rounds, width-wise, so a narrower magazine would still need to be as fat as a .308 one to fit into the magwell properly, with thicker walls to accomodate the two rows of your ammo on the inside, making them bulkier and heavier, not to mention the hassle of designing the whole thing.AR-10 market as a whole is also quite limited compared to the AR-15 and nobody cares about short 30 round mags when they could be shooting 6.5 creedmore instead.
>>64592734>Reduces powder burn efficiency which costs you velocity for the same quantity of powder.Not an issue outside of super highend autism, you get very very minor efficiency losses and a less consistent burn which makes it less attractive to the high precision crowd but it's basically irrelevant for a military cartridge.
>>64592739It's routinely like 10% more powder for the same velocity between a short-fat and long cartridge. That's what makes a cartridge like the .300 WSM an analog to .300 WM despite having about as much powder as a .30-06.
>>64592735Well that's a lie. AR15 and AR10 mags seem to have equal thickness.
>>64592734I simply don't agree.
>>64592905The 308 is wider than 5.56, thus the stack is also wider. How could the mags have the same width?
>>64593132That's perfectly sound logic. They're still basically the same thickness in reality, though. Also, a thinner round still stacks more of itself into a given mag length, so we shouldn't be worrying about width to begin with, you know?
>>64592724>30rds per mag is a worthy benefit.It is not. 25-round 308 are about the same height as 30-round .223 mags, they're fine.Propellant efficiency aside, it would also increase action length and make mags much deeper, meaning potentially fewer mags across your chest rig.It doesn't matter for civilians, and if you're in the military, just get a machine gun if you're willing to go as far as fucking up your cartridges to squeeze in five more rounds in an individual weapon system.Never design cartridges FOR a weapon (unless that's the point, e.g. 300 Blackout etc), it almost always results in less than ideal results. The firearm is a bullet launcher and should be designed as such, while you should squeeze out as much performance of your cartridge as possible because it's borderline impossible to make meaningful changes after the fact.
>>64593183>They're still basically the same thickness in realitytry to fit a corner of an ar10 mag into an ar15 magwell>Also, a thinner round still stacks more of itself into a given mag lengthretarded noguns
>>64594216I think he means the width difference is not significant. It’s like 5mm. Plus there’s no mag width constraint so it’s not like mag width even matters.
>>64595165Precisely. We're literally in a 6ARC thread and Anon cannot see how case width can affect how many rounds fit in a magazine. This is why 30rnd 6ARC mags are so long. All Anon has to do is imagine the reverse. Thinner cases equal more efficiently stacked magazines.
>>64547888>just make 556 go 25-06 speeds with hybrid cases/different alloys
>>64595738>WWII>HMGsyou literal negro
>>64547888>Would the 6mm ARC have been the best universal cartridge (rifle, LMG, HMG) for WWII?I think the thread has answered that question with a "yes but make it a bit longer/thinner for stacking purposes."
>>64597789No, your idea is suboptimal and so is your extremely obvious page 10 bump.
>>64597853.50bmg is plenty long and nobody complains about its powder burn efficiency.
>>64597853Present a better one or submit to ARC.
>>64597920It's not just about powder burn efficiency. Your action length would have to be significantly longer too. Case diameter isn't really an issue (within reason); the British used a rimmed cartridge in WW2 and so did the French until 1932. A longer action would make cycling bolt actions more laborious and potentially decrease the reliability of machine guns. High-capacity magazines simply weren't a consideration in this time period, and it remains almost a non-issue today.I think your cartridge would be 20% longer than .30-06 proportionally. .50 BMG is just a scaled-up .30-06. >>64598132Sure. .276 Pedersen (dia. .2842"), loaded with an improved propellant, necked down to .278" with a scaled down 8mm Lebel Balle N bullet, so you're slugging about 140 grains at 2650-2750 fps with very good BC figures. Optionally, a second, weaker load may be introduced for use in self-loading rifles, with a flat-base FMJ (like 7.5 French Balle C) or solid brass boattail projectile like the Lebel Balle D, around 120 grains. But this is cheating.I don't mind 6mm ARC though, it's a bit light for WWII doctrine but it would just mean slightly more field guns at lower echelons.
>>64598389Would the recoil still be light enough to replace SMGs on the battlefield?
>>6459792050BMG is not terribly long actaully. Proportionally, the case is only a tiny bit longer than the 308’s. Besides, I don’t think anyone cares about the efficiency of the case volume of a cartridge that is hauled around on vehicles, never carried. Like how the cartridge weight of a 50BMG is irrelevant.
>>64598617The weaker load would have similar free recoil energy to 6.5 Grendel, the other one is just a slightly underpowered full power cartridge.
>>64599132>Like how the cartridge weight of a 50BMG is irrelevant.If it's so irrelevant, explain Mk. 323.
>>64601768ehIn practice that would basically just be a 2-cartridge system in most situations for the common soldier.
>>64601778Hmm. I guess maybe they did get too heavy for transport?
