D-56T

The 76.2 mm D-56T series rifled tank gun is the tank gun used on the PT-76, which is the only known armoured vehicle to carry it.
Description.
The D-56T is a anti-tank gun of 76.2mm calibre. It can fire five types of rounds, using a manual loader system, it has an effective fire rate of six to eight rounds per minute. It has a max effective range of approximately 1500 meters, but 400 to 500 metres when on the move, with it being reduced to 650 meters at night. This gun is 42 calibers long. 
A typical combat ammunition load consists of 24 x OF-350 Frag-HE, 4 x sub-caliber AP-T, 4 x AP-T and 8 x BK-350M HEAT rounds. 
The gun is usually mounted in an oval dish-type circular truncated cone turret with flat sloping sides which is mounted over the second, third, and fourth pair of road wheels. All PT-76s have a fume extractor for the main gun at the rear of the turret. Some were fitted with a multi-slotted muzzle brake. Most PT-76s typically feature this gun with a double-baffle muzzle brake, except the PT-76B, typically fitted with the D-56T gun with a two-plane gun stabiliser, a double-baffle muzzle brake and a bore evacuator towards the muzzle.
Ammunition.
The D-56T usually saw itself firing five types of anti-tank rounds. Most rounds that were used on the D-56T were HE rounds, with usually a ready combat load having 24 pieces of OF-350 High Explosive Fragmentation ammunition, and 16 other pieces, with three other types of rounds. Common ammunition types were the OF-350 Frag-HE, BM-354P HVAP-T and the BK-350M HEAT-FS.