APS Underwater Assault Rifle

History

By the late 1960s the Soviet Navy took seriously the danger that enemy combat swimmers could slip into a harbor and plant charges on ships, piers, or submarines. Its answer was a corps of anti-sabotage divers who patrolled the water around naval bases, but these guards had almost nothing to fight with below the surface. A Kalashnikov in a waterproof bag was useless until the diver surfaced, and a knife meant closing to arm's length with an opponent who might be armed with a speargun. The first step was the four-barreled SPP-1 underwater pistol, accepted in 1971, which gave a diver a few short-range shots for self-defense. The navy wanted something with more rounds, more reach, and automatic fire, and the task went to a design team at the Central Research Institute of Precision Machine Building (TsNIITochMash) in Klimovsk led by Vladimir Simonov. The result was the APS, adopted in 1975 and built at the Tula Arms Plant. Like much Soviet special equipment it stayed hidden for years: Western analysts learned of it only after the institute began offering it for export in the early 1990s.

Design

Simonov's engineers first tried conventional rifles underwater and found that a normal bullet loses speed and stability within a few feet. The fix was to change the projectile. The MPS cartridge pairs a sealed case based on the 5.45x39mm round with a slender steel dart about 120 mm long, roughly twenty times as long as it is wide. Fired from a smoothbore barrel, the dart is not spun for stability; instead its flat nose opens a vapor cavity around the body as it moves, and the water flowing past keeps it pointed straight. A tracer version was also produced. The rifle itself is gas-operated and select-fire, and fires from an open bolt so the barrel stays flooded between shots. Its key feature is a self-regulating gas system that copes with the very different resistance the moving parts meet in air and at depth. The very long rounds forced an unusually deep 26-round magazine and a carefully engineered feed system that prevents two darts from feeding at once. The furniture is basic: a sliding wire stock, a fixed notch rear sight, and a post front sight. Later improvements added a perforated gas tube with a deflector to break up the telltale stream of bubbles.

Combat Use

The APS was built for a quiet, defensive job: guarding fleet anchorages, ports, and high-value ships against hostile divers, and arming Soviet naval special forces for their own underwater missions. Its reach underwater falls off with depth, from about 30 meters near the surface to about 11 meters at 40 meters down, because higher pressure collapses the cavity around the dart sooner. That is still well beyond the range of a speargun or the SPP-1 pistol, and the darts can punch through dive suits, helmets, and the casings of swimmer delivery vehicles. On land the rifle is a weapon of last resort: the darts tumble in air, accuracy is poor, and the barrel wears out quickly. Publicly documented operations are rare. One frequently cited case is the protection of the December 1989 Malta summit between George H. W. Bush and Mikhail Gorbachev, where Soviet combat divers armed with APS rifles reportedly guarded the ships.

Significance

The APS was one of the first automatic weapons designed from the start to fight underwater, and the first to see long-term service, and it proved that supercavitating darts could give a diver real automatic firepower. It filled the gap between the knife and the surfaced rifle that had left harbor-defense divers nearly defenseless, and together with the SPP-1 pistol it gave the Soviet Navy an underwater small-arms capability no Western navy fielded in quantity during the Cold War.

Legacy

The APS has stayed in service for half a century with Russian naval anti-sabotage units and special forces, and it has been exported or passed on to several former Soviet republics and other countries, with India's MARCOS naval commandos often named among its users. Its main weakness, poor performance out of the water, led to amphibious successors that can fire both darts and conventional rounds, such as the ASM-DT and the ADS rifle, and to similar designs elsewhere, including China's QBS-06. Today the APS is the reference point for every underwater firearm that followed.

Related entries

AK-47 · SKS · Spetsnaz Trench Shovel

FAQ

Can the APS fire out of the water? Yes, but poorly. The darts tumble in air, accuracy is very limited, and firing in air wears the barrel quickly, so it is treated as an emergency measure.

Why does it fire darts instead of bullets? A normal bullet slows and destabilizes almost at once in water. A long, flat-nosed steel dart creates a vapor cavity around itself and stays stable for tens of meters.

Is the barrel rifled? No. The barrel is smoothbore; the dart is kept straight by the water flowing around it, not by spin.

What replaced it? The APS remains in service. Newer amphibious rifles such as the ASM-DT and ADS were designed to work well both underwater and on land.

Who designed it? A team at the TsNIITochMash research institute led by Vladimir Simonov; it was then produced at the Tula Arms Plant.