The ASM-DT is a Russian folding-stock underwater firearm. It emerged in the 1990s. History and design The introduction of the APS Underwater Assault Rifle solved the problem of how frogmen guarding a naval base could be armed, but there remained the problem of how to arm naval Spetsnaz combat frogmen when they were deployed on assault missions. These forces required a weapon able to provide them with a level of firepower that would be the same whether they were on the surface or underwater. The APS was of little use out of water, because under those conditions it was inaccurate, with an effective range of only 50 meters. In addition, when it was used out of the water, it wore out quickly, with a barrel life dropping from approximately 2000 rounds to only 180 to 200 rounds. For this reason, the naval Spetsnaz forces often fell back on using the SPP-1 pistol for underwater fighting, and the AK-74 rifle for combat out of water. The commandos thought that this arrangement was unsatisfactory, and there continued to be demand for a new weapon, an underwater automatic rifle that would be as effective as an APS underwater and as an AK-74 out of water. As a result, in 1991, at the Artillery Engineering Institute in Tula, Russia, the ASM-DT project was created, with Professor Yuriy Danilov as the rifle's project engineer. To meet the requirements, it had to be considered that a long smoothbore barrel was best for the new rifle to fire underwater, but a rifled barrel was necessary to gain any significant range while above water. To solve this problem and get a true 'hybrid' design, the rifle would have to fire two types of projectile, one underwater, and another above water. The rifle was designed with two feed slots, able to accept two magazines at the same time, to make the transition seamless. Professor Danilov designed the ASM-DT to fire both 5.45 x 39 mm 7N6 (a version of the standard Soviet ammunition), adapted to the caliber of the ASM-DT, and also 5.45 x 39 mm MGTS (aka 5.66×39/120 mm MPS), underwater ammunition like that of the existing APS. The ASM-DT uses the same magazines as the APS while under water, and AK-74 magazines above water. The magazine release shifts forward when using AK-74 magazines, and the gas system automatically adjusts for firing out of water. To enable accurate