If all subsonic rounds are going the same speed, what does it matter which caliber you use? Wouldn't a subsonic 30-30, 7.62x39, or 300 blackout be terminally different if they're all going at the same speed? Or barrel length for that matter?
>>64386280grains, anon
>>64386280As mentioned above… bullet grain weight is a thing. Also what do you need it for? A 32acp ppk needs a lot less suppressor to be quiet vs much bigger bullets…
>>64386280Yes and no, mass matters.
>>64386280Hence the more recent trend of heavy-for-caliber cartridges like 8.6blk and .338 arc. If velocity is predetermined then the only other variable for ballistic performance is bullet construction and weight
>>64386280>If all subsonic rounds are going the same speedOther people have brought up bullet weight.I think it's strange that "slower than sound" is not a single number.
>>64386392Wait till you google what the speed of sound is relative to altitude….
>>64386432>….
>>64386280>If all subsonic rounds are going the same speedThey aren't, fwiw. Rifle specific subsonics tend to be tuned to be about the same (ie, as high as possible with some margin so that they stay sub given some variations in barrel length and altitude) but there's plenty of older subsonic rounds like 45acp that are well below.>what does it matter which caliber you use?Uh, E=mv^2 anon. Yeah we tend to focus on the v with firearms more, but the m does still matter. Air resistance is way more complex, but sectional density is part of it so a heavier round can get you somewhat further with the right shape&material.If you're just having fun plinking at paper you can do whatever, but if you want to hunt with subs terminal energy is relevant.
>>64386383Larger cal subsonic are much louder, bigger hole in the suppressor
>>64386280>lmao@300 b/o when .45acp chads keep winning
Larger diameter means more chance to impact CNS which is the only thing that can stop a fight instantly.>tl;dr: the .45 won
>>64386280In the days of black powder all rounds went the same speed.To make a gun more powerful you had to increase weight.This eventually lead to the 4-bore.Smokeless powder changed all that.To your point, weight is what you want in a subsonic but not only weight. Smaller diameters are easier to suppress and longer rounds tend to have aerodynamic and cross sectional density advantages. You're also seeing crazy things being done with bullet spin rates causing terminal effects. So, no they are not all the same Beyond that, weapon platform is a consideration with rounds like the .300 blackout being easily built into the standard AR giving better modularity and making market share easier to gain, meaning it is more likely for the ammo supply to remain stable.
>>64386280Force is a quadratic with speed, if speed is equal force is linear with mass.A 300 grain projectile at 320m/s has 7.5x the impact force of a 40 grain. One is hitting enemy like a hammer swung at inhuman speed, the other like a pencil
>>64386280F=MxASo if you have more M you get more F even if A is constant.
jesus christ anons>>64391624>Force is a quadratic with speed, if speed is equal force is linear with mass.You're mixing up "force" with "kinetic energy", but yeah KE increases linearly with mass. Momentum also increases linearly with both mass and energy.>>64391628The only acceleration bullets experience after leaving the barrel are gravity and air resistance. Force isn't one of the equations involved in terminal effects.
>>64391628more like p=m·v and E=m·v2
>>64391628Yes, but the more general question of provided relatively the same V and M, what's the advantage of one chambering over another?
>>64391624>Wrote "force" instead of "kinetic energy">Not that it matters since it's completely irrelevant to the point you're trying to make>Then wrote "force" instead of "momentum">Felt the need to clarify a linear relationship with an example>Regardless, there is not a single theory of terminal ballistics that relies on momentum
>>64393721She might be pretty if she you use makeup, smile and put a bag over her head.
>>64393800nta and criticized him a bit earlier, but terminal ballistics isn't all there is either, momentum plays a role in how much a round is affected by wind or anything in the way so if you want to shoot subs longer distance that might be another reason to want more weight. Going to the extreme I'm pretty sure I remember reading somebody got 510whisper to 1moa out to like, 700yd or something wild. At which point the thing would be a fucking mortar round like 300moa of drop but whatever.
>>64393860No, crosswinds don't get affected by momentum, only by bullet mass. It's the same thing in this discussion by happenstance since speed is the constant, but that's just a coincidence. No discussion about reducing vulnerability to crosswinds would ever talk about increasing momentum. The only reason to care about maximizing momentum is if you want to physically push the target by shooting it, or maybe if for some perverse reason you want to increase recoil.
>>64393909>No, crosswinds don't get affected by momentum, only by bullet massAnon, the second law of motion is about momentum, that's what Newton meant in modern terminology. The mass isn't typically changing, so the modern derivation is in terms of derivatives of momentum and time, F=dp/dt. We could talk about reference frames and that even a bullet "just sitting there" on earth is in motion with momentum but the modern definition in physics is that.
