PzGr40
13.08.2011, 20:32
Cutaway model of a 7,5cm Sprengranatpatrone 34 (High Explosive Shell 34) as used in the German 7,5cm KwK.40 tank gun of the Pzkw IV ausf. F2 (and upward models) and in the 7,5cm Sturmkanone 40 of the Sturmgeschutze III ausf.G.
The weight of the complete cartridge is 8,71 Kg. Vo: 550 mtrs/sec.
The projectile body is made of pressed and rolled mild steel. It is threaded in top to receive the Kl.Az 23 Nb Pr. fuze. The projectile body is filled with 0,68 kg amatol. Below the fuze a steel gaine housing is screwed containing the Gr. Zdlg. C98 Np. booster charge. A cartboard smoke generator No.8 -containing red phospor- is placed below the gaine housing. It marks the impact point of the projectile with a smoke plume. The weight of the complete projectile is 5,75 kg.
The shellcase (patronenhulse 6339 St) is steel made (was copper clad, is gone) and is 495 mm long. It contains a bag with 0,725 Kg of Gu. Bl. P –AO powder; square flakes of powder 4x4x0,6mm. Below that, the ignition charge bag is sewed to the main charge bag, containing 20 grams of Nz Man Np powder (1,5x1,5mm). A single stick of powder is placed in the center of the bag up to the base of the projectile. The purpose of this stick is to prevent the bag with powder of falling forward during handling, losing direct contact withe the black powder magazine of the electric primer C/22 or C/22 St in the base of the shellcase. This enshures the powder charge bag is propperly ignited. A small circular pouch of K2So4 is tied to the upper part of the bag charge. It functions as a flash reducer.
The powdercharge of this high explosive shell is much lower than the powdercharge of the Pzgr39 (armour piercing shell). This, because the high explosive shell is not depending upon impact speed. Less powder = less (recoil) wear of the gun = lower logistics and maintenance.
Functioning of the Kl.AZ.23 Nb.(Pr). (Kleiner Aufschlagzunder 23 Nebel Pressstoff / Small Impact fuze for smoke shells 23, plastic)
The Kl.AZ.23 Nb. (Pr) is an impact fuze made of pressed and baked bakelite powder around pressed sheet steel skelleton. This is done to save strategic material as the original Kl.AZ.23 umg was made of aluminium that became scarse. However, in functioning it was fully the same.
The fuze exists of an outer body (1) –steel cage with bakelite., locked up by the bakelite plug (2) , which houses the firing cap housing (3). On top of the plug (2) the collar of centrifugal weights (4) is placed. The transport and firing safety on this fuze exist of a collar of six centrifugal weights, kept in inward position by a foil coil spring (5). In inward position, the centrifugal weights prevent the firing pin (6) and firing cap (red, in the firing cap housing (3) from reaching one another. A small spring (missing here) keeps them apart when the Centrifugal weights swing outward upon firing. Upon firing the centrifugal weights are thrown outward, overriding the foil coil spring (5), enabeling the firing pin and the firing cap to reach one another. Upon direct impact, the wood hammer pin (7) will push the firing pin down into the firing cap. When fired in a low angle to the grond where the projectile will graze the ground, the firing cap housing is thrown forward (negative acceleration) into the firing pin.
The same projectile was used for the Pak 40. The Kwk.42 used the about the same projectile but with the modification of a double drivingband.
Regards, DJH
The weight of the complete cartridge is 8,71 Kg. Vo: 550 mtrs/sec.
The projectile body is made of pressed and rolled mild steel. It is threaded in top to receive the Kl.Az 23 Nb Pr. fuze. The projectile body is filled with 0,68 kg amatol. Below the fuze a steel gaine housing is screwed containing the Gr. Zdlg. C98 Np. booster charge. A cartboard smoke generator No.8 -containing red phospor- is placed below the gaine housing. It marks the impact point of the projectile with a smoke plume. The weight of the complete projectile is 5,75 kg.
The shellcase (patronenhulse 6339 St) is steel made (was copper clad, is gone) and is 495 mm long. It contains a bag with 0,725 Kg of Gu. Bl. P –AO powder; square flakes of powder 4x4x0,6mm. Below that, the ignition charge bag is sewed to the main charge bag, containing 20 grams of Nz Man Np powder (1,5x1,5mm). A single stick of powder is placed in the center of the bag up to the base of the projectile. The purpose of this stick is to prevent the bag with powder of falling forward during handling, losing direct contact withe the black powder magazine of the electric primer C/22 or C/22 St in the base of the shellcase. This enshures the powder charge bag is propperly ignited. A small circular pouch of K2So4 is tied to the upper part of the bag charge. It functions as a flash reducer.
The powdercharge of this high explosive shell is much lower than the powdercharge of the Pzgr39 (armour piercing shell). This, because the high explosive shell is not depending upon impact speed. Less powder = less (recoil) wear of the gun = lower logistics and maintenance.
Functioning of the Kl.AZ.23 Nb.(Pr). (Kleiner Aufschlagzunder 23 Nebel Pressstoff / Small Impact fuze for smoke shells 23, plastic)
The Kl.AZ.23 Nb. (Pr) is an impact fuze made of pressed and baked bakelite powder around pressed sheet steel skelleton. This is done to save strategic material as the original Kl.AZ.23 umg was made of aluminium that became scarse. However, in functioning it was fully the same.
The fuze exists of an outer body (1) –steel cage with bakelite., locked up by the bakelite plug (2) , which houses the firing cap housing (3). On top of the plug (2) the collar of centrifugal weights (4) is placed. The transport and firing safety on this fuze exist of a collar of six centrifugal weights, kept in inward position by a foil coil spring (5). In inward position, the centrifugal weights prevent the firing pin (6) and firing cap (red, in the firing cap housing (3) from reaching one another. A small spring (missing here) keeps them apart when the Centrifugal weights swing outward upon firing. Upon firing the centrifugal weights are thrown outward, overriding the foil coil spring (5), enabeling the firing pin and the firing cap to reach one another. Upon direct impact, the wood hammer pin (7) will push the firing pin down into the firing cap. When fired in a low angle to the grond where the projectile will graze the ground, the firing cap housing is thrown forward (negative acceleration) into the firing pin.
The same projectile was used for the Pak 40. The Kwk.42 used the about the same projectile but with the modification of a double drivingband.
Regards, DJH