by JOSEPH TREVITHICK

Since World War II, America’s elite forces have used quiet firearms for missions where it pays to be discreet. While sound suppressors—commonly referred to as silencers—remain in service today, U.S. commandos once carried revolvers with cartridges specially designed to muffle gunshots.

In the 1960s, the AAI Corporation developed the cartridges for the U.S. Army’s and Navy’s rifles, pistols and shotguns. The ground combat branch’s Special Forces and Rangers tested the unique ammunition in Vietnam.

While they offered many advantages, AAI’s products failed to win any widespread acceptance in the halls of the Pentagon. The rounds were expensive and ineffective at even moderate ranges.

“Throughout the history of firearms, gun noise has been of considerable

concern to the military,” stated a 1968 Army report on silencers. “To the enemy, gun noise reveals presence and, often, the location of the firer, thus inviting defensive or offensive reaction.”

In most modern guns, the sound of the gunshot comes primarily from bottled-up gases escaping as the bullet leaves the barrel—like uncorking a bottle of champagne. A sound suppressor can help muffle the bang by trapping these fumes.

But even with these devices, the gunshot is never entirely undetectable.

In the early 1960s, Army weaponeers looked at alternatives that would completely eliminate the sound of the propellant exploding. So-called “piston cartridges” offered a possible solution.

A normal cartridge contains a casing—which contains gunpowder—and a bullet wedged into an opening at the top. When the propellant detonates, the bullet explosively detaches from the casing, and goes flying through the barrel toward its target.

In a piston cartridge, the case is completely sealed. A plunger transfers the force of the explosion to the slug—like the cue ball striking another in a game of pool.

With the violent reaction contained inside the body of the projectile, the design is effectively silent. A gun shooting these types of rounds produces no muzzle flash or smoke, either.

By 1962, the Army had piston rounds available for .30-caliber rifles and .38-caliber revolvers. The ground combat branch’s fledgling Special Forces soldiers also planned to develop a new weapon to go along with the ammunition.