Earlier this fall, the Russian arms manufacturer Tula Instrument Design Bureau unveiled what it said was the first machine gun that could be used on land or underwater.

The Tula-based company, which has been making precision weapons for almost a century, displayed its so-called ADS amphibious assault rifle in what looked like an expensive fish tank at the Interpolitex 2013 arms show in October in Moscow.

News reports said the weapon would soon be in the hands of Russian special forces and also available to international commandos. While the gun has apparently won orders from customers abroad, it's unclear how many deals the state arms exporter, Rosoboronexport, has actually inked. Sales to specific countries weren't immediately publicized.

The ADS relies on a specially designed cartridge and longer bullets for use underwater.

On land, the rifle shoots standard 5.45mm x 39mm rounds at a rate of 800 shots a minute and with a range of 500 meters, according to a report by RT, the Russia media organization previously known as Russia Today. The performance is similar to the AK-47, also known as the Kalashnikov, on which the ADS is based.

Underwater, it fires bullets measuring 53.5mm long from a slightly larger cartridge and has a range of about 25 meters at a depth of 30 meters, according to RT. A video of the event doesn't actually show the amphibious assault rifle firing rounds in a submerged environment.

The weapon may be of use to Russia's Spetsnaz special forces, who have historically relied on separate rifles for land- and sea-based missions.

Nikolay Komarov, a Tula official, alluded to such when he said, "Until now underwater fighters were compelled to use two types of weapon – for use underwater and the Kalashnikov for overland firing. Now it is only necessary to replace the ammunition magazine," according to RT.

While its international market is likely small, the rifle may also be of interest to commandos or security personnel defending underwater infrastructure.