The Magic Bullet

Sunday, June 13th, 2010

Designing a weapon means making trade-offs — lots and lots of trade-offs — and real life is complicated enough — especially with the “help” of the enemy — that it’s easy to make the wrong trade-offs.

A century ago, it was “obvious” that a soldier needed a powerful, accurate, dependable rifle that could kill the enemy from as far away as possible — something like a deer rifle, around .30 caliber and accurate out to a mile or more.

What’s good for sniping is not necessarily good for storming though, and armies facing entrenched foes began to experiment with pump-action shotguns, which shoot multiple pistol-bullet-sized balls from one 00 (“double-ought”) buck-shot round; submachine guns, which shoot pistol ammo rapidly; the Pederson device, which transforms a battle rifle into a big submachine gun; and light machine guns, which fire full-power rifle rounds, accurately from a bipod, or not so accurately from the hip.

By the end of World War II, the Germans had stumbled onto the modern assault rifle — a machine carbine, really, bigger and with better range than a submachine gun (or machine pistol), but smaller and with less recoil than a light machine gun (or machine rifle).

After the War, the Russians turned this idea into the iconic AK-47. The Americans, on the hand, seemed averse to the whole notion of an intermediate round. Before the war, they adopted the semiautomatic M1 Garand in .30-06 (“thirty ought six”), rather than Pederson’s .276. After the War, they resisted a similar British round and foisted the 7.62×51 mm on their NATO allies — a .30-06 Lite, only not that much lighter.

Like the .30-06, the 7.62 provides accurate long-range fire — but it’s a big, heavy round, with big, heavy recoil. When the semiautomatic M1 Garand evolved into the fully automatic M14, that full-auto capability found very little use; it was just too hard to control. So, instead of a replacement for the standard rifle, carbine, submachine gun, and light machine gun, it became a niche weapon — a semi-auto sniper rifle.

Rather than move to an intermediate round, the American military reacted by going with a glorified .22, the 5.56 mm shot from a plastic M16.  It turns out that a teeny-tiny bullet is still plenty lethal at high velocity, and the Army’s Operations Research Office had concluded that what really mattered was volume of fire — the number one predictor of casualties was the total number of bullets fired. From their research, soldiers rarely fired, unless they had a rapid-fire weapon like a submachine gun, they rarely aimed, because everyone was scrambling for cover, and most combat was at short range, because the two forces had stumbled across one another. Thus, what soldiers really needed was something that could spray a lot of bullets in the general direction of nearby enemies — a fully automatic weapons shooting small, light bullets.

But that’s not how America’s professional Army uses its M16s today. First, American soldiers don’t use true M16s. They use M4s, which are M16 carbines; they have shorter barrels, to make them easier to handle. (The Marines never moved away from the longer-barreled M16.) Second, they don’t rely on “spray and pray” tactics. Semi-automatic fire gets more rounds on target faster than full-auto fire. (The Marines have always emphasized accurate fire.) Third, they don’t stumble upon enemy forces at close range, at least not in Afghanistan — which is why forces in Afghanistan are carrying more and more 7.62 mm rifles and machine guns, even though they’re heavy and require heavy ammo.

So, is there a magic bullet with the best qualities of both the 5.56 and the 7.62? Anthony Williams, co-editor of Janes Ammunition Handbook, doesn’t phrase it that way, but, yes, an intermediate round could be just such a magic bullet. Two suggestions are the 6.8 Remington and the 6.5 Grendel. Notice how they perform in terms of bullet energy vs. range compared to each other and to the old standbys:

7.62 M80, 5.56 M855, 6.8 Remington, 6.5 Grendel

The 6.8 Remington performs as you’d expect — half-way between the larger 7.62 and the smaller 5.56 — but the 6.5 Grendel, like its epic namesake, seems a little bit magical. It starts out with similar energy to the 6.8 Remington, but its more aerodynamic bullet allows it to match the 7.62 at long range.

Arguably, that‘s a magic bullet.

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