06-28-2013, 02:16 AM
stanc Wrote:IMO, the only way to get 6.5 Grendel in service is to adopt it as an across-the-board replacement for 5.56 NATO. If 6.5 DMRs and LMGs proved to be effective enough on the battlefield, infantry units might choose to leave their 7.62 weapons behind when going on patrol.
I think that might well be true for short range combat, where the heavier bullet ought to hit harder. What concerns me is the lack of adequate testing to determine if troops armed with Grendelized M4 carbines can actually achieve higher hit probabilities at long range than with 5.56mm M4s, and if so, just how much better. Regrettably, there is a disturbing absence of hard data to support Grendel proponents.
From a related Thread, Third Generation Battle Rifle, Page 8, Reply #73, An Army Outgunned - Physics Demands A New Basic Combat Weapon, By Joseph P. Avery, PhD, Military Review, July-August 2012 --- ". . . United States combat forces require a versatile and reliable BCW with the ability to incapacitate the enemy at close quarters, with sufficient ballistic energy to smack-down enemy forces with authoritative force at long distance. We can either analyze the newly developed and currently existing 6.5mm cartridges, or attempt an expensive development of a new family of ammunition. . . . The new family of 6.5mm projectiles has over twice the lethality of the 5.56mm M855 NATO round . . . Additional testing is required, and there is always the option of designing an entirely new platform around the current or an enhanced 6.5mm cartridge. It may be prudent to release a group of 6.5mm, M16-chassis weapons for operational field testing in Afghanistan by deployed forces to test against the 5.56mm M855, M855A1 Enhanced Performance Round . . . Research should look into possible enhancement of an even more powerful 6.5mm Enhanced Performance Round . . ."
First, I think most would agree that the 6.5 Grendel, even in its somewhat detuned state to compensate for the additional Bolt Thrust its big butt forces on the standard AR-15 Bolt, represents a quantum performance leap over the 5.56x45mm. That said, what if we reworked the current AR-15 Bolt-Bolt Extension, as has been detailed in these pages, and unleashed the true performance capabilities of the little cartridge that could. And, in that it's already been demonstrated that the 6.5 Grendel, even in its presently detuned state, is far superior to its AR-15 platform brother, the 5.56x45mm, let's compare the Kinetic Energy of an "enhanced" Grendel (read: today's Bolt Gun Grendel) (139-grain Lapua Scenar projectile, BC - 0.615, MV - 2550 fps) with a highly-developed AR-10-length action cartridge, the M118LR (175-grain SMK projectile, BC - 0.495, MV - 2475 fps), from 16" barrels, at 500 yards and 1000 yards:
Cartridge . . Muzzle Velocity . 500 yards (fps/ft.lbs) . 1000 yards
6.5 Grendel . 2550 fps . . . . . 1895/1108 . . . . . . . . . 1375/584
M118LR . . . .2475 fps . . . . . 1693/1114 . . . . . . . . . 1156/519