You seldom hear of guns that fire underwater but here’s one that fires underwater and on land. The TULA Instrument Design Bureau out of Russia has put up its ADS assault rifle as a participant in Interpolitex 2013, the XVII International Arms exhibition in Moscow.
However, the Russian Defense Ministry has to commission it before the combat divers of Special Forces can lay their hands on the weapon. The trick is in the bullets; they are made to fire underwater without getting damp. Compared to its predecessor APS from the 1970s, it lasts more than 180 shots on land, sports a rifled barrel and doesn’t flop before covering even 50 meters.
Used like a normal gun, it chambers 5.45х39 mm rounds, which is the current standard round in Russian assault rifles, and shoots 1600+ feet. Its effectiveness and accuracy are the same, if not greater, than the legendary AK47. The chamber behind trigger assembly, AKA bullpup configuration, maintains the long barrel length while cutting down on overall gun length.
However, underwater it fires different ranges at different depths. These bullets (5.45x39mm PSP/U) travel up to 82 feet at a depth of 100 feet. That’s way beyond the reach of an AK47 with a max range of 6 feet at 15 to 20 feet depth. All you need to change mode is shift the magazine. There’s also a 40mm grenade launcher on the ADS but it seems we’re going to have to wait a while longer for underwater grenades.