T-12 (2A19) - the world's first powerful smooth-bore anti-tank gun. The cannon was created at the Design Bureau of the Yurginsky Machine-Building Plant No. 75 under the leadership of V. Ya. Afanasyeva and L. V. Korneeva. It was put into service in 1961.
The barrel of the gun consisted of a 100-mm smooth-walled monoblock tube with a muzzle brake and breech and clip. The cannon channel consisted of a chamber and a cylindrical smooth-walled guide part. The chamber is formed by two long and one short (between them) cones. The transition from the chamber to the cylindrical section is a conical slope. Vertical wedge shutter with spring semi-automatic. Unitary charging. The carriage for the T-12 was taken from the 85 mm D-48 rifled anti-tank gun.
For direct fire, the T-12 cannon has an OP4M-40 day sight and an APN-5-40 night sight. For shooting from closed positions, there is a C71-40 mechanical sight with a PG-1M panorama.
The decision to make a smoothbore gun at first glance may seem rather strange, the time of such guns ended almost a hundred years ago. But the creators of the T-12 did not think so and were guided by the following reasons.
In a smooth channel, it is possible to make the gas pressure much higher than in a threaded one, and accordingly increase the initial velocity of the projectile.
In a rifled barrel, the rotation of the projectile reduces the armor-piercing effect of the jet of gases and metal during the explosion of a cumulative projectile.
A smooth-bore gun significantly increases the survivability of the barrel - there is no need to be afraid of the so-called "flushing" of the rifling fields.
The smooth barrel is much more convenient for firing guided projectiles, although in 1961, most likely, they had not thought about this yet.
In the 60s, a more convenient carriage was designed for the T-12 cannon. The new system received the MT-12 (2A29) index, and in some sources it is called "Rapier". The MT-12 went into serial production in 1970.
The MT-12 carriage is a classic two-wall carriage of anti-tank guns, firing from wheels like the ZIS-2, BS-3 and D-48. The lifting mechanism is sector type, and the rotary one is screw type. Both of them are located on the left, and on the right there is a pull-type spring balancing mechanism. Suspension MT-12 torsion bar with hydraulic shock absorber. Wheels from a ZIL-150 car with GK tires are used. When rolling the gun by hand, a roller is placed under the trunk part of the bed, which is fixed with a stopper on the left bed. The T-12 and MT-12 cannons are transported by a standard MT-L or MT-LB tractor. For movement in the snow, the LO-7 ski mount was used, which made it possible to fire from skis at elevation angles up to + 16 ° with an angle of rotation up to 54 °, and at an elevation angle of 20 ° with an angle of rotation up to 40 °. The ammunition load includes several types of sub-caliber, cumulative and high-explosive fragmentation projectiles. The first two can hit M60 and Leopard-1 tanks. When installing a special targeting device on the gun, you can use shots with the anti-tank missile "Kustet". The missile control is semi-automatic along the laser beam, the firing range is from 100 to 4000 m. The missile penetrates armor behind ERA ("reactive armor") up to 660 mm thick.
In 1967, Soviet specialists came to the conclusion that the T-12 cannon “does not provide reliable destruction of the Chieftain and MVT-70 tanks. Therefore, in January 1968, OKB-9 (now part of Spetstekhnika JSC) was instructed to develop a new, more powerful anti-tank gun with the ballistics of the 125-mm smooth-bore D-81 tank gun. The task was difficult to fulfill, since the D-81, having excellent ballistics, gave the strongest recoil, which was still tolerable for a tank weighing 36 tons or more. But on field trials, the D-81 fired a 203-mm B-4 howitzer from a tracked carriage. It is clear that such an anti-tank gun weighing 17 tons and a maximum speed of 10 km / h was out of the question. Therefore, in the 125-mm cannon, the recoil was increased from 340 mm (limited by the dimensions of the tank) to 970 mm and a powerful muzzle brake was introduced. This made it possible to install a 125-mm cannon on a three-man carriage from a serial 122-mm D-30 howitzer, which allowed circular fire. By the way, in the OKB-9 on the D-30 carriage, back in 1948-1950, powerful rifled anti-tank guns 100-mm D-60 and 122-mm D-61 were designed. However, for a number of reasons, they did not go into the series.
The new 125mm cannon was designed by OKB-9 in two versions: the towed D-13 and the self-propelled SD-13. ("D" - index of art systems designed by VF Petrov). The development of the SD-13 was the Sprut-B 125-mm smooth-bore anti-tank gun (2A-45M). The ballistic data and ammunition of the D-81 tank gun and the 2A-45M anti-tank gun were the same.
The barrel of the gun consisted of a pipe with a muzzle brake, fastened with a casing in the chamber part, and a breech. Vertical wedge shutter with mechanical (copy) semiautomatic. The loading of the gun is separate-sleeve. Rollback brake hydraulic spindle type, pneumatic knurler.
The 2A-45M cannon had a mechanized system for transferring it from the combat position to the stowed position and vice versa, consisting of a hydraulic jack and hydraulic cylinders. With the help of a jack, the carriage was raised to a certain height necessary for breeding or converging the beds, and then lowered to the ground. Hydraulic cylinders raise the gun to maximum ground clearance, as well as raise and lower the wheels.
The time of transfer from the traveling position to the combat position is 1.5 minutes, back - about 2 minutes.
Sprut-B is towed by Ural-4320 or MT-LB tractor. In addition, for self-propelling on the battlefield, the gun has a special power unit based on the MeMZ-967A engine with a hydraulic drive. The engine is located on the right side of the implement under the hood. On the left side on the frame are the driver's seats and the gun control system during self-movement. At the same time, the maximum speed on dry dirt roads is 10 km / h, and the ammunition load is 6 shots; fuel range - up to 50 km.
When firing direct fire, the OP4M-48A day optical sight and the 1PN53-1 night sight are used. For shooting from closed positions there is a mechanical sight 2Ts33 with a panorama of the PG-1M.
The ammunition load of the 125-mm gun "Sprut-B" includes separate-case loading shots with HEAT, sub-caliber and high-explosive fragmentation shells, as well as anti-tank missiles. The 125-mm VBK10 round with the BK14M cumulative projectile can hit tanks of the M60, M48, Leopod-1A5 types. Shot VBM17 with a sub-caliber projectile - type MI tanks "Abrams", "Leopard-2", "Merkava MK2". The VOF-36 round with the OF26 high-explosive fragmentation projectile is designed to destroy manpower, engineering structures and other targets, the projectile has a powerful explosive charge weighing 3.4 kg of a strong explosive A-IX-2.
In the presence of special guidance equipment 9S53 "Sprut" can fire shots ZUBK-14 with anti-tank missiles 9M119, the control of which is semi-automatic by a laser beam, the firing range is from 100 to 4000 m. Shot weight is about 24 kg, missiles - 17, 2 kg, it penetrates armor behind ERA with a thickness of 700-770 mm.
Nowadays, the armies of the leading Western countries have long abandoned special anti-tank guns, but 100 and 125-mm smooth-bore towed anti-tank guns are in service with some former republics of the USSR and in a number of developing countries. Ballistics and ammunition 125mm gun "Sprut-B", unified with the guns of modern T-80 tanks, are capable of hitting any serial tanks in the world. They also have one important advantage over ATGMs - a wider choice of means of destruction of tanks and the possibility of hitting them point-blank. In addition, the Sprut-B can be used as a non-anti-tank weapon.
In the course of armed conflicts in a number of territories of the former USSR, 100-mm anti-tank guns are mainly used not against tanks, but as ordinary divisional or corps guns. There is no data on the combat use of Sprut-B, but the action of 125-mm high-explosive fragmentation shells on the building of the Supreme Soviet of the Russian Federation in October 1993 is well known.