Assault rifles and their ammunition

[stanc]

It's interesting that the MARS and 6x35 KAC PDW are mentioned in that article, because that caliber would do just as well as 5.56 in close-range engagements, although it lacks the terminal ballistics of 5.56 unless expanding tip projectiles are used. I wonder if a propellant could be developed to get it to match 5.56 velocities out of a 16" barrel, because I could carry 20-24 mags of that and be totally fine.

IMO, the 6x35 is too short range for a general purpose, combat rifle cartridge.

I think a better option is to neck up the 5.45x39 case to take a long, high-BC, .243" projectile, and blow out the shoulder to increase powder capacity.

Such a 6mm "Mini-Grendel" might give muzzle velocity close to that of 5.56 M855, with higher downrange velocities and better terminal effects. And do it with little negative impact on ammo weight or magazine capacity.