The T-90's main armament is the 2A46M 125 mm smoothbore tank gun. This is a highly modified version of the Sprut anti-tank gun, and is the same gun used as the main armament on the T-80-series tanks. It can be replaced without dismantling the inner turret and is capable of firing armour-piercing fin-stabilised discarding sabot (APFSDS), high-explosive anti-tank (HEAT-FS), and high explosive fragmentation (HE-FRAG) ammunition, as well as 9M119M Refleks anti-tank guided missiles. The Refleks missile has semi-automatic laser beam-riding guidance and a tandem hollow-charge HEAT warhead. It has an effective range of 100 m to 6 km, and takes 17.5 seconds to reach maximum range. Refleks can penetrate about 950 millimetres (37 in) of steel armour and can also engage low-flying air targets such as helicopters.
The NSV 12.7mm (12.7×108) remotely controlled anti-aircraft heavy machine gun can be operated from within the tank by the commander and has a range of 2 km and a cyclic rate of fire of 700–800 rounds per minute with 300 rounds available (the NSV was replaced by the Kord heavy machine gun in the late 1990s). The PKMT 7.62mm (7.62×54mmR) coaxial machine gun weighs about 10.5 kg while the ammunition box carries 250 rounds (7,000 rounds carried) and weighs an additional 9.5 kg.
Like other modern Russian tanks the 2A46M in the T-90 is fed by an automatic loader which removes the need for a manual loader in the tank and reduces the crew to 3 (commander, gunner, and driver). The autoloader can carry 22 ready-to-fire rounds in its carousel and can load a round in 5–8 seconds. It has been suggested that the automatic loaders on modern T-90 tanks have been modified to take advantage of newer ammunition such as the 3BM-44M APFSDS, which like the US M829A3 penetrates armour better than the previous shorter rounds. HEAT rounds that can be fired from the 2A46M includes the 3BK21B (with a depleted uranium liner), 3BK29 (with a credited penetration of 800 mm RHA equivalency), and the 3BK29M (with a Triple-tandem charge warhead). Additionally the T-90 features the Ainet fuse setting system which allows the tank to detonate 3OF26 HE-FRAG rounds at a specific distance from the tank as determined by the gunners laser rangefinder, improving its performance against helicopters and infantry. Accurate firing range of the HE-Frag-FS 10 km, APFSDS 4 k
The T-90 is fitted with a "three-tiered" protection system. The first tier is the composite armour in the turret, consisting of basic armour shell with an insert of alternating layers of aluminum and plastics and a controlled deformation section.
The second tier is third generation Kontakt-5 ERA (explosive reactive armour) which significantly degrades the penetrating power of kinetic-energy APFSDS ammunition and also these ERA blocks give the turret its distinctive angled "clam shell" appearance. ERA bricks are also located on the turret roof and provide protection from top-attack weapons. The turret's forward armour package, in addition to the ERA and steel plating, contains a composite filler of Russian composite armour sandwiched between upper and lower steel plates. The composite armour results in a lower weight and improved protection when compared with steel-only armour.
The third tier is a Shtora-1 (Russian: Штора-1 or "curtain" in English) countermeasures suite, produced by Elektromashina of Russia. This system includes two electro-optical/IR "dazzlers" (i.e. active infrared jammer) on the front of the turret (which gives the distinctive "Red Eyes"), four laser warning receivers, two 3D6 'smoke' grenade discharging systems and a computerised control system. The Shtora-1 warns the tank's crew when the tank has been 'painted' by a weapon-guidance laser and allows the crew to slew the turret to face the threat. The infrared jammer, the TShU1-7 EOCMDAS, jams the semiautomatic command to line of sight (SACLOS) guidance system used by some anti-tank guided missiles. The smoke grenades are automatically launched after Shtora detects that it has been painted. The smoke grenades are used to mask the tank from laser rangefinders and designators as well as the optics of other weapons systems. Indian T-90S tanks are not equipped with the Shtora-1 countermeasures suite. They will be equipped with the LEDS-150 Land Electronic Defence System.
compiled by XENOCIDE