ADS amphibious rifle

The ADS is an assault rifle of Russian origin specially made for combat divers. It is of a bullpup layout and is chambered in the 5.45x39mm M74 round. The ADS can adapt a GP-30 type underbarrel grenade launcher and optical sights.

Early combat diver weaponry
For several decades, Soviet and then Russian combat divers and naval commando units were armed with special weapons for underwater combat, including the SPP-1 pistol and APS underwater assault rifle. The main drawback of these weapons is that their effectiveness (and life expectancy) for use above the water is severely degraded compared to standard 'above water' weapons. Therefore, combat divers and other Spetsnaz units, when engaged in amphibious operations (below the water and above), had to carry on the mission two types of weapons - one for underwater use and another for use when on shore or on board of enemy surface vessels. The first known attempt to produce a single weapon which could be effectively used either below or above the water was the ASM-DT experimental 'dual-medium' or amphibious assault rifle, developed in Tula in around 2000. The main problem with ASM-DT was that it still had to use extremely long, specially designed underwater ammunition when submerged, which necessitated overly long receiver, complicated magazine well of adjustable size and two types of magazines. This was found unsuitable for combat use, and further development commenced at the famous arms development facility KBP (Instrument Design Bureau) in Tula. By 2005, design team at KBP has successfully developed effective underwater ammunition which retains the compact size of the standard issue 5.45x39 7N6 ball (as well as 7N10 and 7N22 AP) rounds, and thus can be loaded and fired from standard AK-74-type box magazines, and, more importantly, fired from the same chambers and barrels that would accept the 'above-water' 7N6 ammunition.

New cartridge
This new cartridge is known as 5.45x39 PSP, and is externally similar to standard 5.45x39 ammunition except that it has a different bullet shape. Internally it differs in having a long bullet, which has specially calculated shape and protrudes back into the cartridge case all the way to the bottom, with overall bullet length being about 53mm (2.1 inch), compared to overall cartridge length of 57mm. There are two types of PSP ammunition, the 5.45 PSP (combat ammunition) with hardened steel projectile weighting 16 gram (muzzle velocity on air about 330 m/s) and 5.45 PSP-U (practice / training ammunition) with bronze projectile weighting 8 gram (muzzle velocity on air about 430 m/s). Effective range with PSP ammunition varies from 25 meters at 5 meters depth to 18 meters at 20 meters depth; effective range of the PSP-U training ammunition when below the water is about half.

Rifle info
The rifle was designed by Russia's Tula Instrument Design Bureau. It is equipped with a 40 mm grenade launcher (no mention is made of grenades for underwater use). The weight of the gun with the grenade launcher is approximately 4.6 kg. The weapon uses 5.45х39 mm bullets and fires at a firing rate of 800 shots/min with a range on land of 500 m. The weapon's effective underwater firing range when using the specially designed cartridge is about 25 meters at a depth of 30 meters and 18 m at a depth of 20 m (the underwater cartridge very similar in external appearance to the standard 5.45x39 ammunition except for a different specially calculated bullet shape). The length of the bullet is 53.5 mm compared to an overall cartridge length of 57mm.

Trials
The ADS is said to be under extensive field trials by undisclosed units of Russian Naval special forces. If adopted, it will replace APS underwater weapons and, possibly, some AK-74M general issue assault rifles in service with Russian Navy special operation units and other Russian special forces, which might be engaged in underwater operations (security, counter-terrorism in the sea, etc.).