The barrel LB-3 manufactured as a bar with a two-chamber muzzle brake and navintnym breech. Vertical wedge gate, taken from the ZIS-2 with virtually no configurations. Semiautomatic follower (mechanical) type.
Hydropneumatic recuperator. Brake hydraulic recoil. The lifting mechanism — a sector, the rotary push-type helical gear. There is a sector balancing mechanism and a torsion cushioning.
Direct-fire was used telescopic sight OP1-2, there is also the possibility of setting Braids under panorama of Hertz. In the chassis used wheels from GAZ-1 with a modified hub.
At Gap in October — November 46th, the proving ground tests conducted 45-millimeter PTP-BL 3. During field tests laid out in 1544 produced 866 shots were fired. In this test done due to bad extraction cartridges, which by the end of the test reached 50%.
Ballistic Data LB-3, acquired during the field tests:
— armor-piercing projectile BR-271 weighing 3.14 kg (weight of the charge 1355 g) had an initial velocity of 985 m / s, with all the pressure in the barrel was 3162 kg/cm2;
— projectile fragmentation of O-271U weight 3.75 kg (weight Charge 925 g) had an initial velocity of 693 m / s, with all the pressure in the barrel is 1680 kg/cm2. Range shot at an angle of 15 degrees was targeting 6480 meters;
— piercing projectiles BR-271P weighing 1.79 kg (weight of the charge 1685) had an initial speed of 1274 m / s, the pressure in the bore at all it was equal 3082 kg/cm2.
The system, according to the conclusion of the commission of ground tests, did not survive, but for the upcoming testing needed structural improvements. It was also noted that a large weight and a huge Khobotova pressure from anti-tank gun LB-3 do on the battlefield even worse conditions of transport compared with opytneyshemi systems C-15 and 4-26. This conclusion can be regarded as a death sentence.
So Makar, ballistics, anti-tank guns LB-3 and ZIS-2 match.
Technical properties of light 57 mm anti-tank gun LB-3:
Standard — Plant 92;
Full length of the barrel — 4340 mm/76 calibres.;
The channel length — 3950 mm/69, 3 calibres;
Length rifled — 3420 mm;
The steepness of the rifling — 30 calibres.;
The volume of the bolt — 2.05 l;
Number of grooves — 24;
Rifling depth — 0.9 mm;
The width of rifling — 5.45 mm;
The field width — 2.0 mm;
Weight gate — 31.0 kg;
Weight of the barrel with the shutter — 334 kg;
The vertical guidance — from -9 ° to +17 °;
The angle of the horizontal guidance — 58 °;
Normal recoil length — 960-965 mm;
Length rollback limit — 720 mm;
The height of the fire lane — 630 mm;
Length with gun shifted housings — 6250 mm;
Width guns at spaced housings — 3860 mm;
Width tool when shifted housings — 1660 mm;
Stroke width — 1500 mm;
Panel thickness — 7 mm;
The diameter of the wheels — 730 mm;
Weight sliding parts — 382 kg;
Weight rocking parts — 461 kg;
Weight Shield — 65 kg;
Weight carriage without a shield and weapon — 406 kg;
The weight is in the firing position — 818 kg;
Rate — 15-25 shots per minute;
Carriage speed on the highway — 45 km / h.