there are basically two infantry cartridges in the world as of this moment, the 7.62x39mm (model 43) russian for the kalishnikov rifle, and the 5.56x45mm u.s. military round for the m-16/m-4 family of rifles. the chinese have a dog in the fight, but, it has yet to gain much traction anywhere outside of china.
take you pick. both the kalishnikove and m-4 cartridges have their virtues, both their faults, yet both are well balanced cartridges that tend to get the job done, which is to be effective combat weapons out to 300 to 350 yards or so .... though, to get hit by either out past that is probably going to put something of a damper on your day.
i propose another cartridge, the "308 rem spc," which i think would be superior to either the russian or the current u.s. offerings.
it is based on simplicity itself. if you take the remington 6.8mm spc (special purpose cartridge), open the neck to take a .308" diameter bullet of moderate weight (say 130 to 135 grains or so) there it is. simple, straight forward, and very much (in all probability) very similar in performance and lethality to the model 43 russian. maybe a little better paper ballistics, but in the real world, not so very different.
the one deficiency perceived in the 5.56x45mm cartridge is terminal lethality when used against enemy soldiers. and, some argue is not as effective in this regard as the russian round. i have no dog in that fight, never having been shot by either, and hoping not to be shot by either. 6 of one, 1/2 dozen of the other, as the saying goes.
but, for those who do argue the superiority of the larger round, my suggestion of the .308 rem spc cartridge should handily dispose of any doubters about the performance in the field of u.s. infantry small arms.
i am working on a reduced power load for the 8mm mauser rifle using imr 4198 powder, and a charge weight of 25-27 grains of powder, to get a plinking round of around 1700 fps or so. just for shits and giggles, i went to the parts racks, and fetched up a 7.62x39mm empty case, and an empty 6.8mm spc case. the 6.8 is a little longer, the 7.62 rooskie a little bigger around at the bottom the case, near the rim .... oddly enough, at the shoulder dimension, both are nearly exactly the same.
as it turns out, the 6.8 rem has more case capacity than the 7.62 russian .... the charge of 25 grains of imr 4198 fills the russian to the case shoulder and a teensy into the neck, while it barely fills the 6.8 rem to the junction of the case body and the shoulder. so, the 6.8mm has an advantage in similar weight bullets in terms of velocity and energy, but i doubt very seriously that you would be able to tell the difference if struck by either.
my guess that the .308 rem spc would have nearly identical performance to the russian model 43, namely around 2350 to 2400 fps at the muzzle out of similar length barrels. in short, my .308 rem spc proposal would be for all intents and purposes, very very very similar in terms of ballistics to the russian round.
so, why bother?
well, it is not a bad thing to have a round the same as the model 43 russian. it is, in fact, a recognized world standard in infantry cartridges.
but, the .308 rem spc has the virtue of "being invented" here, and being american. there are, moreover, advantages to the round i am purposing, and they mostly have to do with compatibility with existing u.s. weapons systems. 1.)such a round as i propose would readily fit in magazines currently used in m-16/m-4 variants of the ar rifles. 2.)they would operate at mean pressures very similar to the 5.56x45mm stoner system cartridge, requiring no significant changes in spring rates and strengths, and no large fuss in determining where to locate gas ports and sizes of gas ports .... no brainer issues, to any relatively competent engineer or engineers in this field. 3.)no new projectiles would have to be developed, as .308 bullets in the 130 to 135 grain range bullet abound, and would be readily altered to the style of current weaponry. 4.)recoil levels would be very low, very similar to the russian model 43. 5.)and, the basic case, the 6.8mm rem spc is widely made by u.s. manufacturers, and would require a ridiculously low effort in making tooling for easy mass production of the ammunition, and would use powders and components very similar if not identical to those being used to make the 5.56x45mm/.223 remington ammunition.
as a matter of fact, you would not be able to tell the difference looking at a weapons system in 5.56mm and 6.8mm without looking at the script on the barrel. added to the advantages mentioned above, the manual of/at arms would not change one iota.
so, i make the modest proposal. the time has come to upgrade from the 5.56mm cartridge to a little larger one, and this would be an almost impossibly easy way to go about it.
it makes sense. it is, therefore, probably doomed at conception. but, i have tried. the rest is up to the people who do this stuff, who shall most likely not be satisfied with something so butt wipe simple.
john jay @ 01.30.2021