go to a 1-9" twist like the belgians
Nope and incorrect.
USMC is issuing Barrier Blind (SODT) ammo in Afghan and Iraq.
C77/M855 was good ammo at the time it was adopted, however research in the field has created better bullets.
Years ago HSM was loading the AA53 77gr OTM in Orange Boxes for competition.
Enter 9/11 and the ammo was used operationally, BlackHills picked up the contract and bullet setback was noticed in the Mk262 Mod0.
Mod1 was designed with a cannelure to get a better case mouth seal to stop bullet setback, it has a minor degredation on accuracy (still sub-MOA) and also increase terminal effectiveness.
However it was a conventional OTM, and the SMK is not the best performer in short barrels.
Enter various loading for SOCOM.
The BlackHills 70gr "BROWN TIP" Optimized 5.56mm was standardized, in certain communties for vertain ammunition.
However the USMC had intiated a RFI for a Barrier Blind ammo - in seeing the problems with the Mk262 on intervening barriers and vehicles.
Crane has picked up on the Barrier Blind ammo and it is now being fielded.
5.56mm works.
7.62mm still has a role however, as it is simply a bigger and better performing round (projectiles being equal).
Yes 6.8 SPC does offer advantages, as does 6x35 in some situations and various other cartridges.
There is a push in the Army and USMC to adopt the SOF Arms Room concept. A concept that is very valid (different uppers that can be chosen for mission upon need).
However buying every soldier 3 uppers to use on a host lower is expensive as is maintaining them.
Frankly a 10-12" CQBR, a 14.5-16" GP, and a 18-20" SPR upper and the accompanying optics would give soldiers a great deal of capability. Adding a 16" and 20" 7.62mm interchangeable platform would be a big boost too (1-2 per section/squad).
The 6.5 and 6.8 proponets often miss the necessity of having the Section/Squad Beltfeds in the same caliber...
Until FN or someone else rolls out a beltfed LMG in those cartridges then its all blowing smoke.
Taking the Arms Room concept to a futher level.
8" 6x35 Knight's upper
12.5" 6.8 SPC upper
16.5" 6.8 SPC upper
common lower
LMG in 6.8
Micro LMG in 6x35
16" 7.62 NATO
20" upper for above
LMG in 7.62mm NATO
In a perfect world with infinite funding...
and a perfect logisitical train that never has availability or wrong ammo shipped...
Until that day arises, which I can never see happening, then it will be a continual argument.
And even if it did, some armchair asshat will be arguing that the guy on the ground either picked the wrong combo, or should have something esle.........
Sigh.