New Army "Caliber Configuration Study"

[Tony Williams]

Tony, perhaps I wasn't clear, but what I meant is that I'd like to postulate a 6.5 M855A1, with its two-part copper and steel construction, that exactly matches the shape or form factor of the 6.5mm 112gr GS Custom monolithic in order to preserve that bullet's BC, as nearly as possible.

Photo concept attached.

That bullet looks very good, John. It's simpler than the M855A1 because it doesn't include the half-jacket, but inserts the steel penetrator straight into the brass body. It looks like a half-way point between the bullets which ARDEC made for their calibre comparison tests a few years ago (which had a smaller steel element IIRC), and the RUAG HC bullets which are mostly steel penetrator with a smaller brass "shoe" around the base (see below). My only concern with these designs is the potential effect on the BC of the join between the steel and brass bits, and whether the steel tip is so easy to work to the optimum shape.



By the way, talking about efficient Russian designs take a look at the bullet from the experimental Russian 6 x 49 Unified round - it weighed only around 5g (77 grains) - shown here next to the 5.45 x 39:



Finally, just to illustrate the issue over bullet length and form factor, here's a selection of 5.56mm military bullets: 55 grain M193, 62 grain M855, 62 grain M855A1, 77 grain MK262. You can see the length issue with the lead-free bullets, and the fact that despite its extra length, the MK262 FF is actually no better than the M855's - it improves in long-range performance only by being heavier.