27 Jan 18
The Ballistic Facts of Life:
The Pentagon’s unwavering loyalty to the 5.56×45 cartridge may be faltering, at long last, but we are once again confronted by the Laws of the Universe.
New materials, new coatings and other surface treatments, new machining methods and technology, new propellants, all help, but “game-changing miracles,” though much falsely claimed, are pretty much confined to the Old Testament!
Autoloading military rifles, chambered for 5.56×45, are suitable, maybe even ideal, for domestic personal defense and as police patrol rifles.
But, as a “main-battle-rifle,” the caliber is inadequate, in both range and penetration. And, all the “wonder bullets,” proposed and issued, since the 1960s have fallen far short of adequately addressing these two critical issues.
And, short barrels make a bad problem even worse!
So, here is the unhappy truth:
While DOD wants a more powerful cartridge, effective to 500m, they don’t seem to consider that it is invariably going to require a rifle that weighs more and has a longer barrel than the current M4.
Barrel length, overall rifle weight, propellant capacity, bore diameter, durability, effectiveness:
All these parameters have to be balanced against unavoidable trade-offs, inherent with each.
A large ratio of propellant to bore-diameter (1) requires a long barrel length and (2) shortens barrel life.
A large bore diameter and (of course) a heavier bullet requires a heavy barrel and large cartridge cases, which means increased recoil and decreased magazine capacity. Big case-heads require big bolts.
It seems we have be trying to find the best compromise since the Mauser Brothers first introduced bolt-guns and smokeless propellent, back in the 1800s!
In fact, the original 7mm Mauser was a pretty good military cartridge. Still is!
Then, there was the 280 British, 276 Pedersen. Probably adequate, but never adopted. The 6.5×55 Swedish is in the same category.
A military cartridge needs (1) generous case-taper for easy feeding and extraction, (2) limited pressure for reliability, durability, long barrel-life, and slow heat build-up, (3) a ballistically-efficient bullet, heavy and tough enough for adequate penetration, and (4) sufficient muzzle velocity to keep the bullet supersonic out to at least 800m.
The new generation of cartridges, including the 224 Valkyrie, 6.5 Creedmore, 260 Remington, et al make good, long-range sniper calibers. But, with a light, skinny bullet, combined with a barrel with a fast twist-rate, we inherit rapid heat build-up, short barrel life, and the requirement for a long barrel. Significant muzzle velocity is sacrificed for every centimeter of barrel-length reduction. Thus, any of these calibers, in a short-barreled rifle (carbine), represents a contradiction of terms!
The first thing DOD is going to have to acknowledge is this:
When they really insist on a 500m rifle with acceptable penetration, that rifle will need at least a twenty-inch barrel and will have to be chambered for a cartridge with a bullet as least twice as heavy as that of the current 5.56×45.
Unhappily, what DOD has fanatically avoided confronting for the past forty years is the fact that they are going to have to, at long last, actually train real riflemen to kill individual enemy soldiers, one at a time, with accurate, semi-automatic rifle-fire.
I’m not at all sure they even know how anymore!
DOD could have an adequate main-battle-rifle, as described above, complete with appropriate optics, rails, etc, in the hands of front-line Soldiers and Marines in less than a year, all for a fraction of the cost of a single stealth fighter, if there were any will at the highest levels to actually get it done and finally put this issue behind us.
I’m less optimistic than I was a year ago!