Responses: 2
SGT Chester Beedle
The problem is that most of the 7.62 ARs are not very reliable, or they are stupidly heavy.
The best, fast, solution would be to adopt a better round for the 5.56mm like the 50grain TTSX all copper bullet made by Barnes, or the MK318 (or SOST) round that has been tested in combat. If penetrating body armor is the question, then the M995 will do pretty damn well, but currently only comes belted for the M249. People have been stripping them off the belts to load into mags.
A midsized round like the 6.8 SPC (developed by a guy from 5th SFG and someone from the AMU) or even the 6.5 Grendal would be a great choice for the rifleman and the SAW. Increased range, and increased lethality at all ranges. Without adding 4 pounds to each rifle while also reducing ammo capacity of the soldier.
The Army has rejected a 6.5mm ish round multiple times for whatever reason. Between the world wars the .276 Pederson was developed and the M1 Garand was originally chambered in that. But we had so many 30-06 round we wanted to stick with that. At the end of WW2 the British developed two .270ish rounds... eventually we forced the .308/7.62x51... to use all the left over 30 caliber bullets, and an attempt to replicate the 30-06. Then a mere ten years later we went in the far opposite direction and came up with the .223 Remington (which later became the 5.56x45).

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