pzgr40
Well-Known Member
Cutaway model of a “Shell, QF (Quick Fire), High explosive 95mm Tank and SP howitzers Mark 1A”. This shell was used in the Cetaur tank, the Churchill VIII tank and the Alecto Self propelled gun for infantry close support. At the start the primary role of these vehicles was the laying of smoke screens and attacking pillboxes and field fortifications with a shaped charge shell.
The gun was made of the existing parts of other guns; the barrel was 2,4 mtrs of barrel of the 3,7” Anti Aircraft gun, the breech block was from a 25 pounder field gun and the recoil mechanism was borrowed from a 6 pounder anti tank gun.
The shell body is made of mild pressed and rolled steel. A flange is roll crimped in the base of the projectile body (is difficult to see in this picture). As the shell body is pressed over a rod, small cracks may appear in the base of the shell. When fired, high pressure hot gasses of the propelling charge could than reach the explosive charge, causing a premature. Therefore, the flange is roll crimped in the base, acting as a gasket. In top of the shell body a threaded ring is placed which receives the nose Fuze No. 119B.
In the shell body a flange with a pipe is placed which houses the ignition charge, which consists of two Tetryl powder filled rubber bags. A cartboard tube is placed around the pipe and in the explosive charge. Below the pipe a cartboard tube is placed housing the bakelite smoke box, filled with red phospor. This enhures the point of impact is marked by a smoke cloud which allows for aiming corrections. The main charge in the shell body consists of Amatol (Amonium nitrate mixed with TNT), topped with an approximately 0,5cm thick layer of pure TNT around the cartboard tubes, to ignite the less sensitive Amatol.
Functioning of nose fuze No.119 B1 (Pict-03):
In safe condition the firing pin is kept in locked position by the centrifugal bolt (horizontal pin) whom is blocked from moving outward by the set-back safety (vertical pin on creep spring). Before firing the steel safety cap on the nose is removed, exposing the thin brass wind cap that protects the firing pin. On firing the set-back safety pin moves down, overcoming the creep spring, thus releasing the centrifugal safety bolt. The centrifugal force moves the pin outward, where it hooks behind a rim in the hole, preventing it from moving back upward. The firing pin also moves down at setback, however the flange on the firing pin has a chamfered edge as well as the centrifugal bolt -hooking the two into each other-, and as the firing pin moves down with set-back on firing, it prevents the centrifugal bolt from moving outward. As soon as setback has diminished (constant velocity) the centrifugal bolt moves outward thereby releasing the firing pin. The only thing that keeps the firing pin away from the firing cap is a weak creep spring. At impact the firing pin is hammered in the firing cap (red).
When a graze shot occurs, the deceleration throws forward the cylinder containing the firing cap into the firing pin, overcoming the creep spring. A flame sensitive detonator is placed below the firing cap, boosting the flame of the firing cap. A booster is srewed into the base of the fuze housing a spring loaded safety slider in top. The slider keeps the flash channel out of line until centrifugal force moves it outward, placing the firing cap, the flash channel and the booster in line.
The brass shellcase is 206mm long and has a small propelling charge of 12 oz 4dr of WM 042 cordite. The sticks are 1mm in diameter and appr. five inches long. Approximately 1/3 of the bundle forms the centre bundle -tied together with sewing silk-, placed upon the No.1 percussion primer, the other 2/3 is placed around the centre bundle. This fixates the lower part of the bundle around the primer. A glazeboard disc in top of the charge keeps the propelling charge centered in top.
Vo: 330 mtr/sec (1100 ft/sec)
Range 7,315 mtrs (8000 yards)
Rate of fire: 7 rnds/min
Shell weight: 25 pounds (11 kg)
Regards, DJH
The gun was made of the existing parts of other guns; the barrel was 2,4 mtrs of barrel of the 3,7” Anti Aircraft gun, the breech block was from a 25 pounder field gun and the recoil mechanism was borrowed from a 6 pounder anti tank gun.
The shell body is made of mild pressed and rolled steel. A flange is roll crimped in the base of the projectile body (is difficult to see in this picture). As the shell body is pressed over a rod, small cracks may appear in the base of the shell. When fired, high pressure hot gasses of the propelling charge could than reach the explosive charge, causing a premature. Therefore, the flange is roll crimped in the base, acting as a gasket. In top of the shell body a threaded ring is placed which receives the nose Fuze No. 119B.
In the shell body a flange with a pipe is placed which houses the ignition charge, which consists of two Tetryl powder filled rubber bags. A cartboard tube is placed around the pipe and in the explosive charge. Below the pipe a cartboard tube is placed housing the bakelite smoke box, filled with red phospor. This enhures the point of impact is marked by a smoke cloud which allows for aiming corrections. The main charge in the shell body consists of Amatol (Amonium nitrate mixed with TNT), topped with an approximately 0,5cm thick layer of pure TNT around the cartboard tubes, to ignite the less sensitive Amatol.
Functioning of nose fuze No.119 B1 (Pict-03):
In safe condition the firing pin is kept in locked position by the centrifugal bolt (horizontal pin) whom is blocked from moving outward by the set-back safety (vertical pin on creep spring). Before firing the steel safety cap on the nose is removed, exposing the thin brass wind cap that protects the firing pin. On firing the set-back safety pin moves down, overcoming the creep spring, thus releasing the centrifugal safety bolt. The centrifugal force moves the pin outward, where it hooks behind a rim in the hole, preventing it from moving back upward. The firing pin also moves down at setback, however the flange on the firing pin has a chamfered edge as well as the centrifugal bolt -hooking the two into each other-, and as the firing pin moves down with set-back on firing, it prevents the centrifugal bolt from moving outward. As soon as setback has diminished (constant velocity) the centrifugal bolt moves outward thereby releasing the firing pin. The only thing that keeps the firing pin away from the firing cap is a weak creep spring. At impact the firing pin is hammered in the firing cap (red).
When a graze shot occurs, the deceleration throws forward the cylinder containing the firing cap into the firing pin, overcoming the creep spring. A flame sensitive detonator is placed below the firing cap, boosting the flame of the firing cap. A booster is srewed into the base of the fuze housing a spring loaded safety slider in top. The slider keeps the flash channel out of line until centrifugal force moves it outward, placing the firing cap, the flash channel and the booster in line.
The brass shellcase is 206mm long and has a small propelling charge of 12 oz 4dr of WM 042 cordite. The sticks are 1mm in diameter and appr. five inches long. Approximately 1/3 of the bundle forms the centre bundle -tied together with sewing silk-, placed upon the No.1 percussion primer, the other 2/3 is placed around the centre bundle. This fixates the lower part of the bundle around the primer. A glazeboard disc in top of the charge keeps the propelling charge centered in top.
Vo: 330 mtr/sec (1100 ft/sec)
Range 7,315 mtrs (8000 yards)
Rate of fire: 7 rnds/min
Shell weight: 25 pounds (11 kg)
Regards, DJH
