The APS (Avtomat Podvodnyj Spetsialnyj = Special Underwater
Assault rifle) was developed during the early 1970s at
TSNIITOCHMASH (Central Institute for Precision Machine building) by
the team lead by V. Simonov. APS has been in active service with
combat divers of the Soviet and Russian Navy since circa
1975.
The APS is designed for special underwater cartridges, which fire
5.66 mm needle-like projectiles 120 mm long. The projectiles are
stabilized using a hydrodynamic cavity, generated by the flat point
of the projectile. The cartridges use standard 5.45 x 39 cases,
sealed from water. The APS itself is a relatively crude, smoothbore
arm, with a gas operated, rotating bolt action, fired from an open
bolt. Single safety / selector switch is located at the left side
of the receiver and allows for single shots and full automatic
fire. The gas system features a patented self-adjusting gas valve,
which allows the gun to be fired both underwater and in atmosphere.
The simple trigger unit allows for single shots and full automatic
fire. The rate of fire under water, as well as the effective range,
depends on the actual depth. Sights are crude: a non-adjustable
open notch rear and post front. The retractable buttstock is made
from steel wire. The most complicated thing in the whole design is
the feed system, which includes several parts to avoid double and
even triple feed with the extremely long projectiles. Unusually
deep (front to back) magazines are made from polymer and hold 26
rounds.
It must be noted that while APS could be fired "above the
water", it should be done only in the case of emergency. According
to the available sources, the expected service life of the APS when
fired "in the air" degrades severely, and the effective range is
limited only to several tens of meters. So, the APS is useful only
under the water, where it is quite efective.
