Cutaway model of a 76,2 x 385mm UOF-354M HE cartridge for M1942 (ZIS-3) field gun. This gun also formed the main armament of the T34/76.
Muzzle velocity: 610 m/s.
Weight of projectile :6,21 kg.
length of complete cartridge: 640mm.
Length of projectile: 343 mm.
The OF-350A HE projectile body is made of machined cast iron. The lower part of the projectile body is filled with a mixture of potassium nitrate and TNT (cheaper bulk explosive), the top part is filled with pure TNT, ensuring the explosion of the top part is strong enough to ignite the less sensitive explosive in the lower part of the shell body. The projectile uses the KTM-1 impact fuze.
Functioning of the KTM-1 fuze:
The KTM fuze has a two piece steel body, with a detonator /booster screwed to the base. A sheet brass pressed safety collar (17 ) with four outward bent fingers keeps the inertia activated spring (6 ) loaded bushing (7 ) in upward position, and the firing cap (18 ) housing (8 ) forced in the lower position, keeping the firing cap away from the firing pin (19 ). Upon firing, the bushing (7) moves down due to inertia, riding the spring (6), bending the fingers of the safety collar (17) inward. The inside of the bushing (7) has a chamber machined, in which the four fingers of the safety collar expand. When acceleration decreases, the spring (6) moves the collar/bushing/ firing cap housing forward, resting the firing cap against the stop ring (4). The firing cap has been placed so much forward now that the firing pin can reach the firing cap upon impact, either the firing cap can move forward into the firing pin upon graze. The stop ring is a flat 0,1mm thick ring with four tiny fingers pointing inward, bent upward by the firing cap housing (8 ) due to inertia upon graze.
A cart board spacer set is placed in the shell case, just below the projectile, locking up the powder grains in the lower position.
Regards, DJH
Muzzle velocity: 610 m/s.
Weight of projectile :6,21 kg.
length of complete cartridge: 640mm.
Length of projectile: 343 mm.
The OF-350A HE projectile body is made of machined cast iron. The lower part of the projectile body is filled with a mixture of potassium nitrate and TNT (cheaper bulk explosive), the top part is filled with pure TNT, ensuring the explosion of the top part is strong enough to ignite the less sensitive explosive in the lower part of the shell body. The projectile uses the KTM-1 impact fuze.
Functioning of the KTM-1 fuze:
The KTM fuze has a two piece steel body, with a detonator /booster screwed to the base. A sheet brass pressed safety collar (17 ) with four outward bent fingers keeps the inertia activated spring (6 ) loaded bushing (7 ) in upward position, and the firing cap (18 ) housing (8 ) forced in the lower position, keeping the firing cap away from the firing pin (19 ). Upon firing, the bushing (7) moves down due to inertia, riding the spring (6), bending the fingers of the safety collar (17) inward. The inside of the bushing (7) has a chamber machined, in which the four fingers of the safety collar expand. When acceleration decreases, the spring (6) moves the collar/bushing/ firing cap housing forward, resting the firing cap against the stop ring (4). The firing cap has been placed so much forward now that the firing pin can reach the firing cap upon impact, either the firing cap can move forward into the firing pin upon graze. The stop ring is a flat 0,1mm thick ring with four tiny fingers pointing inward, bent upward by the firing cap housing (8 ) due to inertia upon graze.
A cart board spacer set is placed in the shell case, just below the projectile, locking up the powder grains in the lower position.
Regards, DJH
