Did you know that the size of the radius created by stacking 7.62x51 NATO cartridges (ie. magazine curvature) is almost exactly 1 meter?Pretty neat huh
>>64265026>magazine curvatureIs there a way to calculate this without drawing the entire circle like a retard?
>>64265041Actually mathing this out is something I'm going to leave as an exercise to the reader, but you would pull up the case specs and do some basic trig on it. See pic rel.
>>64265026>1 meter diameter pan magazineimagine
>>64265026It's called called taper, OP
>>64265041Yeah it's basically hs level geometry/math
>>64265158>pulls out tape measureholy shit
>>64265158*2 meter diameter
>>64265267HOLIER SHIT
pan magazines were pvre sovl
>>64265136> Actually mathing this out is something I'm going to leave as an exercise to the readerOk Fermat.
>>64265026>the size of the radius created by stacking 7.62x51 NATO cartridges (ie. magazine curvature) is almost exactly 1 meter?I just did the calculations and you're way off opwhy come here just to lie?
>>64266526Show your work
>>64266793did it on paper
>>64266811You have a phone
>>64266817camera broke
>>64266793R≈11.9−11.5(11.9+11.5)/2×39.6≈1,160mm≈1.16m(≈46in)like I said: way off
>>64266891This anon is right.
>>64266891>>64266952(me)But I think if you used the rim diameter of 12.01mm you’d get a slightly smaller radius since the rim does not actually follow the case taper perfectly. It’s ever so slightly too wide. It should be just under 12mm (11.99mm)
>>64266891Not only are your notations pure shit, learn to use brackets, (calculating what you wrote results in -5316.28), your numbers inaccurate, the shoulder diameter is 11.53mm and the case rear od is 11.96mm, you are also using for the length the distance from the backface to the shoulder even though you aren't using the rim diameter for your case rear od.Now, to do it properly I'm going to calculate it with the following formula using the expectation that a rimless cartridge will not have rims touching each others.(rear od * dist. to shoulder) / ( rear od - shoulder od) + dist. to backface(11.96 * 35.77) / (11.96 - 11.53) + 3.85 = 998.76 mm ≈ 1 m
>>64268714>inaccurate*inprecise
>>64265026Did you know that the M16A4 is exactly 1 meter long?
>>64268714thanks anonI knew giving a shit answer (whatever gpt spewed in this case) would make some autist do the actual work
>>64268961You think I didn't use gpt? You just gotta learn to use it properly.
>>64268961>>6426902480085
Why aren't all cartridges in one shape? There must be some mathematical formula for the optimal shape.
>>64270105It's called 9mm and 556 mr autist
>>64270105Because it's all just tradeoffs.More taper? ok your extraction is more reliable but now your magazines are highly tapered and longer for the given cartridge size and powder volume.
>>64270105>rimmed for easier headspacing (can also help extraction)>rimless for easier feeding>rebated rim for retaining the same bolt face, extractor, and ejector as another cartridge>tapered for easier extraction (can also help feeding)>bottlenecked to put a fatter charge of powder behind a bullet (can help feeding too)>rimfire to be inexpensive>heeled bullet because we didn't yet know better>roundnosed bullet because pistol calibers don't really go fast enough so might as well go for weight (or you want a rifle that shoots a big bullet)>pointy bullet because a rifle cartridge and barrel can drive it to sanic speeds>uncircumcized brass casing for obturation in revolversThere are different kinds of purposes and ideas.
>>64270390So sad nobody has made the god tier Kellgren rimfire cartridge into reality. Designed for rifle level pressures and autoloaders feeding from magazines it would be an excellent assault rifle cartridge.
>>64270405I shall hereby humiliate you, hesitant anon.
>>64265026Wow thanks ian that sure is some useful information1
>>64270434>rimfireCompletely ridiculous.
>>64270477Based on what? Give the rifle a double prong striker with a strong strike and there will be absolutely zero misfires.I never get misfires with my Tikka T1x because it has a beefy strong striker that absolutely smashes the rim.
>>64270496Because for an intermediate rifle cartridge you want a lot of pressure, and rimfire depends on a fairly soft brass case, you're gonna get blown cases unless you want it to be fucking weak.
>>64270633Steel cases and it's not even such low pressure.
>>64270633stfu no guns faggot you don't know what you're talking about. go back to /lgbt/
>>64270105There isn’t.I’ll give you an exampleTake a 5.56 and scale it up isometrically. 2x in every dimension. The end result will have the same silhouette as 5.56. It will have 8x as much propellant (thus 8x the energy) but only 4x as much bullet frontal area, thus 2x the sectional energy. You can’t keep everything constant.There is a mathematical optimum (sorta) to how a cartridge should be configured but only if you have sufficiently many constraints imposed like COAL, barrel length, intended range, cartridge mass, etcPistol cartridges are an example of that. There are severe constraints on the cartridge’s overall size and the barrel’s length. The intended range is not very far. This basically forces a straight-walled design. There are some bottlenecked ones, but none are anywhere near as bottlenecked as rifle cartridges.
>>6427043480kpsi 5.7x28 with .204 VLD’s. It’s just that, but better. You’d maybe get like 800ft*lbs out of it and retain that energy in flight pretty well. But the combat load could be 500 rounds.
>>64270909>There is a mathematical optimum (sorta) to how a cartridge should be configured but only if you have sufficiently many constraints imposed like COAL, barrel length, intended range, cartridge mass, etcguns don't work off coal dumbass the work off blackpowder
>>64270434The 4.5mm MKE cartridge and its rifle was not an appealing proposition at all.>actually necked down .22WMR casing>case so thin that it needed a locked breech action to not kaboom>case also so thin that it could not be closed bolt for fear of cookoff>solid copper bullets, so in spite of zippy velocity it probably icepicked like a fucker>inherent propensity for priming compound to break out of its rim cavity from rough handling was almost certainly not solved, so even with dual firing pins reliability was most likely never great>also fucking rimfire cartridges in a double-stacked magazine, enjoy thatThis thing would probably be like a worse H&K MP7 at best.>>64270755Unless they were using steel .22WMR casings as a base for this, I don't see how this would be the case. Also in spite of the whopping high +3200fps, that's with a very light little 24gr solid copper bullet, it might just do a bit of cool cavitation or fragmenting at really close ranges, but it must have been awful at range.The fact that Interdynamics never saw any interest in this thing and abandoned the project without much more work suggests that they knew fully that it wasn't viable.You're never gonna match 5.56mm or 5.45mm performance with this thing.>>64270835Get raped and kill yourself, nigger. There are virtually only drawbacks to making the cartridge rimfire, because you need your firing pin to be strong enough to crush the rim (but without piercing it), yet you also want the case to be strong enough to contain high pressures, so you can have a higher powder charge and heavier projectile to have not-shit ballistics.
>>64273325>Get raped and kill yourself, nigger. There are virtually only drawbacks to making the cartridge rimfire, because you need your firing pin to be strong enough to crush the rim (but without piercing it), yet you also want the case to be strong enough to contain high pressures, so you can have a higher powder charge and heavier projectile to have not-shit ballistics.retard bullshitter other anons have already proven you wrong. just make them steel case and use duel firing pins you fucking mong. you have no guns, you do not shoot guns, you only play call of duty and you're probably from some 3rd world shithole
>>64273349Go back to the 19th century, rimfire troon.
>>64273325>>case so thin that it needed a locked breech action to not kaboomAnd? Locked is necessary for high pressures.>>case also so thin that it could not be closed bolt for fear of cookoffAnd? A small zippy bolt means it's still plenty accurate.>>solid copper bullets, so in spite of zippy velocity it probably icepicked like a fuckerNot true, the bullet is extremely long and would instantly destabilize in flesh.>>propensity for priming compound to break out of its rim cavity from rough handling not a real thing>>rimfire cartridges in a double-stacked magazineDid you even read the paper? The possibility of rimlock was eliminated by the case geometry meaning that is it the only rimfire cartridge actually well suited for magazines.>Unless they were using steel .22WMR casings as a base for this, I don't see how this would be the caseDude it's an experimental project. Of fucking course they will use off the shelf components where possible for testing etc. If further developed they would have eventually made their own cases.
>>64273514>Locked is necessary for high pressures.Yes, but that's more of an example about why the strength of the case isn't an irrelevant factor. .22WMR (and its .17 caliber derivatives) is similar in that it really needs a delayed or locked action for self-loading, and if you're going to make the action more complex for what's ostensibly an infantry rifle, you may as well make a better case overall.>A small zippy bolt means it's still plenty accurate.Still a perceptibly longer lock time.>The possibility of rimlock was eliminated by the case geometryYes, but your magazine is also a half-circle, admittedly not that big and with 50 whole rounds, but they're very small rimfire rounds.
>>64273514What the fuck is it with 4.5 interdynamics simps pushing towards rimfire cartridges? It’s the only time anyone argues in favor of rimfire. That’s outdated case technology, get over it. The idea still has merit, just with a rimless centerfire case.>5.7x28 case>80kpsi>.204 VLD with L:D of 6:1>~2” COAL>500 round combat loadBetter in every way than 4.5 interdynamics, could even get close to 5.56 in retained energy at 300 yards, maybe even surpass it in sectional energy. Here’s a powley sheet. Something in that ballpark.
>>64273514>not a real thingYes, it is. Priming compound, aside from the possibility of being applied unevenly, can potentially dislodge from part of the rim. Centrifuging the cases helps make both less likely, but it can still happen.>If further developed they would have eventually made their own cases.Yeah, but they obviously had a goal in mind for cartridge size and case capacity, and it was framed as an assault rifle, when it's actually much closer to something like the P90, and they clearly thought that it being rimfire was a selling point.If you compare to another micro-caliber cartridge concept, the Heckler & Koch 4.6x36mm, setting aside its projectile design and just focusing on its case, it's not as tiny as a .22WMR with a long bullet in it, it's got plenty more case capacity. It's also a rimless centerfire cartridge, so you can have dead reliable priming, and stacking 20 or 30 of them together doesn't make for a banana of a magazine (or packet clip, like was the case for the 4.6x36mm for some of the rifle's iterations).Using available components make sense, but there were a lot of other options which could be worked with, .30 Carbine, .221 Fireball, hell, even using something like .357 Magnum or .38 Super as a parent case if you were dead set on stacking in a half-circle.I appreciate George Kellgren's creativity, a lot, but he's designed vastly more practical weapons than the MKR.
>>64273043Idk if you’re joking or not, but incase you’re being serious, COAL = Cartridge Overall Length.
>>64273043I realized right when I hit “post” that you were just joking.
>>64273986I think that micro caliber (4.5mm/.17-.18 caliber) could maybe work for a PDW kind of weapon, like the MP7 and P90, but I have some considerations for it.>you want it as a bullpup to maximize barrel length, so at the least something similar to the P90's form factor, MP7 isn't giving you as much>the existing 4.6x30mm and 5.7x28mm cartridges could both have a bit more ass in them>probably NOT revisit the older 4.6x36mm's spoon tip projectile, but other novel bullet designs can be helpful for the niche>obviously centerfire>maybe perfectly straightwalled sides so you can do the P90 style magazine, or a tapered rimmed cartridge if you wanna do a half-circle>much stronger case means you can do something like a delayed and closed bolt action>cyclic rate should probably be south of 1000rpm, making a given magazine last longer
