"Summary for Colonel-General of Artillery comrade Voronov
regarding systems: M-42, 104-K, and M-6
A. M-42
This modernization consists of increasing the muzzle velocity by lengthening the barrel and increasing the density of the propellant. Aside from the barrel, all other parts of the gun are taken from the mass production version of the 45 mm mod. 1937 anti-tank gun.
Only the following parts are changed:
regarding systems: M-42, 104-K, and M-6
A. M-42
This modernization consists of increasing the muzzle velocity by lengthening the barrel and increasing the density of the propellant. Aside from the barrel, all other parts of the gun are taken from the mass production version of the 45 mm mod. 1937 anti-tank gun.
Only the following parts are changed:
- Semiautomatic coupling: lengthened by 150 mm.
- The trigger mechanism plunger is lengthened by 150 mm.
- The return mechanism cylinder groove is shortened by 20 mm.
- The spindle length diameter is changed by 0.06 mm.
- The return mechanism springs are stock, but are at the upper limit of their load.
The ammunition (armour piercing and high explosive shells), shell casing, and gunpowder are taken from the stock mass production gun, only the weight of the propellant is changed.
The M-42 system is undergoing factory and proving grounds trials.
B. M-6
The modernization consists of:
- Increasing the muzzle velocity by lengthening the barrel and increasing the density of the propellant.
- Altering a series of assembles in order to simplify production.
Aside from the barrel, the following assembles are changed:
- Upper mount
- Turning mechanism
- Elevation mechanism
- Suspension springs
- Cradle
In addition, several parts of the return mechanism have been altered:
- Springs
- Brake cylinder
- Brake rod
- Breech elements
The ammunition is stock. The increase in propellant weight is analogous to that of the M-42.
The M-6 has not finished factory trials. During factory trials, extended surging of the system (up to 250 mm) was observed, and the axle was deformed during transport (from telegram sent by regional engineer comrade Anisimov).
C. 104-K
The 104-K is a completely new anti-tank gun with the muzzle velocity of 960 m/s.
The oscillating part of the gun is completely different from the stock anti-tank gun, including the breech and semiautomatic system. The mass of the system is 120 kg greater than the stock gun. The barrel can be locked in the recoiled position during travel.
Technologists conclude that this system is complicated and requires improvement.
The ammunition used is from the 45 mm AA gun (45 ZIK) which is not in use. An experimental prototype is only being built.
M-42 | M-6 | 104-K | |
Barrel | New | New | New |
Breech and semiauto | Stock | Altered | New |
Recoil brake | Stock | Altered | New |
Cradle | Stock | New | New |
Upper mount | Stock | New | Stock |
Lower mount | Stock | Altered | Stock |
Aiming mechanism | Stock | New | Stock |
Suspension | Stock | Stock | Stock |
Suspension springs | Stock | New | Stock |
Trails | Stock | Altered | Stock |
Shield | Stock | New | Stock |
Shells | Stock | Stock | From 45 ZIK |
Casings | Stock | Stock | From 45 ZIK |
Travel lock | Stock | New | New |
Mass (full combat) | 570 kg | 600 kg | 650 kg |
Muzzle velocity | 885 m/s | 880 m/s | 960 m/s |
Barrel length (calibers) | 68.8 | 67.1 | 66.7 |
Barrel length (mm) | 3087 | 3012 | 3000 |
Acting Chief of the ArtKom 2nd Department, Engineer-Colonel Komarov"