The conclusions of trials of American armour piercing-tracer M-62 shells against armour described in table #17 and illustrated in the graph shows that:
- The penetration quality of American 76 mm AP-T shells can, under favourable conditions (angle/distance), effectively penetrate targets (tanks, SPGs, bunkers) with armour up to 120 mm thick.
The penetration quality of domestic 76 mm AP-T shells (blueprint #2-09038) allows for effective penetration of only 100 mm of armour under identical conditions to American 76 mm AP-T shells.Given identical thickness of armour and angle from normal, the quality of the American shell guarantees penetration from larger distances than domestic shells, 1000 m at normal and 300 m at an angle.
The advantage in the quality of American M-62 AP-T shells is explained by a superior design, well selected materials, and thermal hardening of the shell.
- Compared to domestic shells (blueprint #2-09038), American shell hulls have better robustness in impact against armour.
The condition of various parts of the hull after striking armour is worth mentioning. The tip of the hull, even after penetrating 100 mm of armour at 30 degrees, remains intact in most cases. The driving band and post-driving band sections are not destroyed, but the post-driving band section deforms, which prevents the explosive filler compartment from bursting. The shell has a good gradient of hardness along its length, the hardness chosen is optimal, providing good penetration qualities and satisfactory robustness.
- Convenience of the crew: The overall planning of the fighting compartment and assignment of functions to crew members is poor.
In the SPG tested, the gunner cannot independently fire indirectly, the commander does not have constant and uninterrupted access to the loader by voice or signs, as he is on the other side of the gun and must use a wired communication device.
The loader only has half of the fighting compartment available to him, which lowers the convenience of servicing the gun.
As a result of proving grounds trials of the 3" (76.2 mm) American M7 gun in the volume of 415 shots (25 increased charge), the ANIOP deems that:
- The presented American self propelled gun, capable of firing armour piercing and high explosive shells, can be used to combat enemy tanks and armoured cars, suppress enemy strongholds, destroy lights obstacles, and enemy forces.
- During trials, all gun and recoil mechanisms worked satisfactorily.
- The muzzle velocity of the 6.75 kg M-62 AP-T shell with 2.095 kg of gunpowder (brand 12/7) and peak pressure of 2580 kg/cm² is 810 m/s.
- The gun stability is satisfactory.
- The precision of fire against a vertical target with the M-62 AP-T shell is satisfactory. Mean deviation was measured to be the following:
- At 500 m: 0.06 vertical, 0.10 horizontal
- At 1000 m: 0.14 vertical, 0.24 horizontal
- When firing the M-62 AP-T shell, the departure angle of the shell from the gun is almost zero.
- The maximum and practical rate of fire with shells kept in the ammunition racks is 4-6 RPM. When shells are kept outside of racks, the maximum rate of fire is 10 RPM.
- The penetration of the 3" (76.2 mm) American M-62 AP-T shell is shown in the table below.Armour typeAngle (degrees)Minimum speed (m/s)Equivalent distance (m)75 mm homogeneous K=240030626140090 mm homogeneous K=26000600160030730600100 mm homogeneous K=22500666110030768300120 mm homogeneous K=24000739500
- Robustness trials of elements of the American 3" (76.2 mm) M-62 AP-T shells at increased propellant charge showed satisfactory results."