New Army "Caliber Configuration Study"

[Tony Williams]

A comment on bullet design: it does not necessarily follow that a lengthened bullet has a better Form Factor, if the extra length just goes into the shank, leaving the nose and tail profiles the same.

This can be demonstrated by comparing the 7.62mm M80 with the M118 sniper loading (both lead-cored). The M118's FF is almost exactly the same; it has a better BC simply because it's heavier.

Extra length can permit a better FF by allowing a longer, more tapered ogive - but only if the COAL permits this. Which it doesn't in the 7.62x51 (or the 5.56x45, or the .300WM, or the .338LM).

The US has a long tradition of designing cartridges with COALs too short to permit the use of high-BC bullets with long ogives. The 6.8mm Rem is perhaps the most extreme recent example of this - the 6.5mm Grendel is an exception.

One of the key design points of any new military cartridge should be that the specification must allow the use of long-ogive bullets, since they can provide a significant improvement in long-range performance without any extra power, weight or recoil. Apart from slightly longer gun actions and magazines, it provides extra performance at no cost.

Choosing the .338NM rather than the .338LM for the LDAM MMG would be a big step in the right direction.