a reply to: machineintelligence
You've actually got your comments almost completely backwards.
But before u get to that I'd like to very clearly state that there is no such thing as stopping power in the first place, but even if there were
modern 5.56 ammo would still have more for a very wide variety of reasons.
Also, 7.62x39 and likely 300 blackout too actually have better base barrier penetration than 5.56 rather than the reverse. This is why 7.62/300 blk
are actually preferred by some nation's for cqb and urban combat is specifically their more innate "barrier blind nature's". For those with the money
and technology to develop/afford barrier blind 5.56 this is not much of an issue because their 5.56 is equal or better to the heavier slower rounds
wrt barrier blind performance by quite a bit.
There's also some who go to subsonic 300 or x39 specifically for suppressed use that still allows you to equal or better standard ak performance to at
or a bit beyond 300 meters simply by switching mags to ones loaded with supersonic ammo. This is however an implicitly acknowledged and pretty
specialist in nature compromise though.
The reason for this being is that an akm in 7.62x39 with standard 16.25" barrel or the great majority of 300 blk guns with barrels usually
substantially less than 16.25" in length give up a literal 66% in range to an m855a1 or mk318 mod 1 loaded 14.5" barrel m4 or m4a1 which can be used
to hit man sized targets out to 500 meters quite easily compared to scoring hits with a 300 blk or 7.62x39 gun firing at man sized targets at 300
meters (their max effective range).
Depending on your training budgets, average skill level of your people, and multiple other things including terrain and opfor characteristics this may
or may not actually be a massive issue.
Finally, which exact 6.5 round are you saying is equivalent to 7.62x51 exactly? There are a great many 6.5 rounds which range from vastly inferior to
massive superiority over 7.62x51!
I'd hazard a guess that at least one or two of your 6.5 rounds you're thinking of as as good are in fact just severely ocerhyped by mainly severely
Even the "superior" 6.5's will actually require development to fully exploit their ballistic superiority while still meeting requirements for
specialist ammunition such as tracer and others that a military chambering will require.
What's even more frustrating is that in general militaries want or even need these specialist rounds to ballistically match the trajectories of their
gp loadings which often forces suboptimal compromises in the GP projectiles design and performance. Many if not most of the 6.5 wonder rounds people
tout will promptly become shockingly less impressive the instant the GP round and the tracer variant must be trajectory matched.
TL;DR making military ammo is at least an order of magnitude harder than marketing guys and bad historians will cop to it being.