The gunner T-54/55 Fire Controls

the d-10 100mm high-velocity gun, 53.5 caliber length barrel. high muzzle velocity (895 m/s) gave armor penetration performance late world war ii standards. designed equip su-100 tank destroyer gun (the d-10s), after world war ii mounted on t-54 main battle tank d-10t (for tankovaya, tank adj.). world war ii era, 1960s, there few types of tank rounds offered d-10 gun both of t-54/55 , su-100 (before phased out of service).

these uof-412 15.6 kg high-explosive fragmentation 1.46 kg tnt warhead. 100mm of-412 fragmentation warhead 60% heavier in both total weight , bursting charge equivalent 88mm tank guns found on german tiger tanks. antitank ammunition available world war ii until late 1960s based on ubr-412 round: br-412 aphe projectile, br-412d , br-412b ammunition becoming available shortly after world war ii. br-412 aphe round penetrate 150mm of steel armour @ distance of 1000 meters. due increase of armour protection on tanks in post world war ii era, t-54/55 forced rely on heat (shaped-charge) ammunition engage tanks 1960s before more modern kinetic energy rounds developed, despite relative inaccuracy of ammunition @ long ranges. shortage of heat rounds in soviet tanks during world war ii solved not long afterwards once soviet industry passed devastation of war. high-explosive anti-tank rounds included 3ubk4 3bk5m warhead (which penetrate 380mm of steel armour ), later replaced 3ubk9 3bk17m warhead. these rounds main heat munitions t-54/55 received until developments of barrel-launched 100mm guided missiles in 1980s.

the gunner s sight modified on , on again , adapted new kinds of ammunition. @ first there scales hef shells (of-412) full , reduced powder charge, aphe shell (br-412) , coaxial machine gun. in 1964, soviet designers started work on improved 3ubm6 hyper-velocity armour-piercing discarding sabot round (as opposed aphe rounds d-10 used before). in 1967, 3bm6 hvapds round entered service. replaced 3bm8 projectile in 1968, tungsten carbide penetrator, giving 318mm penetration against steel armour @ point-blank range. sabot rounds effective due accuracy , high-velocity gave rounds flat flight trajectory. tank gunners in soviet army taught can hit tank-sized target without having input range scales if firing sabot round target being @ or on outskirts of 1000 meter ranges. effectiveness of point-and-shoot method brought combat efficiency of t-54/55 step closer more modern tanks such leopard 1 , t-64.

new scales added tsh2b-32 sight allowing range input new types of ammunition. dial left side of gunner s eyepiece served selecting of x3.5 times x7 times zoom. gunner turn on sight illumination during night time, made distance , aiming markings become visible in red against dark background of night. accurate shooting during night gunner use tpn-1 device working on active infrared principle. electro-optical monocular telescope x5.5 times zoom , 6 degree field of view. effective range of illumination 600–800 meters. when firing main gun, automatic screen closed short time. otherwise, observation tpn impossible due bright flash. in addition, light muzzle flash can burn out emitter layer of picture converter make tpn useless. tpn connected stabilized parts of main gun. therefore accurate aiming on move during night possible well. big floodlight (the l2ag, so-called luna floodlight) placed on right side of turret, elbow fastened stabilised main gun , serves purpose field lighting. fixture floodlight follows movement of cannon, yet has calibrated shine center chevrons of tpn sight. periodic crew work required. shooting tpn relatively easy. there main triangular chevron in center of reticle. upper tip represented br-412 aphe land @ 700 meter range, , machine gun rounds land @ 500 meter range. many variants of tpn-1 adopted t-64, t-72 , t-80 tanks improved active , possible passive night vision.