Optimized Caliber

[stanc]

A starting point is to ask: Are we OK with small arms that would be bigger and heavier than the current M4/M16 series? Longer cartridge overall lengths start a growth spiral.

Paul wants to keep the M4 chambered for 5.56 NATO, so there wouldn't be a weight spiral for carbines. What he proposes is a special, long-loaded, high-pressure 6.5 Grendel solely for an LMG (and maybe DMR).

One niggling point I had meant to make: I believe M855A1 is not ONLY copper and steel, but includes a bismuth alloy core under the steel penetrator. (I THINK it's bismuth!)

The previous version (M855A1 LFS) did have a bismuth alloy slug behind the steel tip. However, that caused problems, so the current loading (M855A1 EPR) has a copper slug.

Below:

[Penetrator] [M855A1 LFS ------------------->] [M855A1 EPR ->