Cutaway models of a 5cm SprGr.Patr.38 -high explosive- shell and a 5cm PzGr.Patr.39 -armour piering- shell, fired from the Ww2 German 5cm Pak 38 (Pak = Panzer abwehr kanone / anti tank gun).
During the Spanish civil war it became soon clear that the 3,7cm Pak 36 gun was insufficiënt in knocking out tanks, later during the invasion of Russia this became rather painfully clear with the appearence of the T-34 to which the Pak 36 had no more effect than scratching the paint. The German army nicknamed the 3,7 Pak 36 ‘Heeresanklopfgerät’ , which translates as the ‘army’s doorknocker’.
As the lack of penetrating power of the Pak 36 was recognized early on, in 1938 Rheinmetall-Borsig had allready started with the development of a more powerfull anti-tank gun; the 5cm Pak 38. This gun had a barrel length of 60 calibres (60x5cm =3m rifled barrel) and was the only gun that was able to knock out a T-34 face on, although at a short distance only. The even heavier armoured KV-1 tank could only be knocked out with a tungsten carbide cored PzGr,40 shell, also at close distance. As it soon became clear that even the Pak 38 would become obsolete soon, the 7,5cm cm Pak 40 was designed and taken into service, and this gun was able to knock out any allied tank at longer ranges.
The Pak 38 was mainly used as a drawn gun, but was also used in the SdKfz 234 Puma armoured car.
The cartridges -although in slightly modified version- were also used in the 5cm BK-5 (Bord Kanone / Aircraft Gun) as used in the Me262 U4 and the Me-410 A1/U4, the difference could be found in the powdercharges in the shellcase and the usage of the C22 Electric ignited primer in the shellcase.
Left, the a 5cm SprGr.Patr.38
The projectile consists of a steel body, with an adjustment ring screwed in top. The AZ.39 fuze is screwed in top of the adjustment ring. This adjustment ring enables a pre-packed explosive charge to be glued in the projectile body with magnesiumkit (kind of predecessor of polyester resign), locking it up with the adjustment ring.
The explosive charge consists of two parts , the top cilinder of 15 grams of Nitropenta, the rest of the cartboard container filled with FP-02 (TNT). In top of this FP-02 charge smoke box No.12 is placed, enabling to observe the impact point of the projctile.
Total weight of the explosive charge is 0,185 kg, of which 0,17 kg is explosives.
Functioning of the AZ-39 impact fuze:
The AZ-39 is an all aluminum fuze. A slider prevents the firing pin from moving downward. The slider is held in place by two radial placed pins that fall in recesses in the side of the slider. These two pins are held inward by a bronze ring shaped interrupted blade spring. Upon firing these two pins are thrown outward (centrifugal force), releasing the slider. A steel ball is placed in an axial hole that is drilled under a 2 degrees outward angle to the top of the fuze. When fired, the acceleration keeps the ball in the lower position, as soon as the velocity is constant, the centrifugal force will make the ball creep the wall of the hole upward until it falls into the hole in the slider. As the slider becomes heavier on this side it will pull the slider outward, releasing the hole for the firing pin. On impact the firing pin is driven into the firing cap of the Duplex detonator, exploding the detonator and the projectile.
The shellcase is steel made and 420mm long. The percussion primer C12 or C12 N.a. is placed in the base of the shellcase. This primer has it’s own black powder magazine to ehshure a fast and even ignition of the main charge in the shellcase. In the German nomenclature the shellcase is named ‘Patronenhulse 6360 St’
The powdercharge in the shellcase consists of a double bag filled with powder. The top bag, containing the main charge is filled with236 grams GU. Bl.P –AO- flaked powder 4x4x0,6mm thick. Below that, a bag containing 30 grams Nitrocellulose rifle powder 1,5x1,5x0,5mm is placed to ensure the main charge in the top bag is ignited instantanoiusly. A single pipe of tubular powder 7mm in diameter with a hole of 5mm through and a length of 345mm is placed in the bag, forcing the bag in the forward position, so the lower bag is forced upon the percussion primer and does not move forward when handled or loaded in the gun, leaving a void between the percussion primer and the bag.
The reason the high explosive shell has a smaller propulsion charge than the armour piercing shell is that the high explosive shell does not need high speed to function, and can therefore do with a much lower speed, lower barrel pressure and as a consequence of that lower barrel wear. The sight of the gun must however be switched from AP to HE as the HE shell has no flat trajectory like the AP shell, but a curved trajectory.
Right, the PzGr.Patr. 39
The projectile is flat based and has a pointed nose, the nose is hardened. There are two ways of manufacturing the projectile, the first is a one piece projectile with a hardened nose, in the second method a nose of better quality alloy steel is friction welded https://www.youtube.com/watch?v=BwC0zXpoZjw
to a lesser quality steel lower body portion. It is called the 5cm Pzgr.39 V. (Verbundgeschoss). This is profitable as the use of expensive alloy steel is highly reduced.
In the base of the projectile an ogive shaped hole is drilled, containing a pressed in charge of 17 grams Nitropenta (NP15 = Nitropenta with 15% of wax). Below this charge a two piece aluminum P2 detonator is placed, and below that the Base fuze (BdZ) 5103 is screwed into the base of the projectile.
On top of the projectile the soft steel piercing cap is soft soldered on top of the projectile. This cap ensures the force of the impact is divided over the entire hardened nose, avoiding it from shattering upon impact. Another advantage of using a piercing cap is that if the projectile hits a target at an agle (f.i. the front hull armour of a T-34 or Sherman tank), the piercing cap will ‘weld’ itself tot he armor and rotate the projectile in a more favourable angle towards perpendicular to the armour during the piercing process. This will improve piercing and reduce the chance of the projectile bouncing off.
The first 5cm PzGr projectiles had no piercing cap and were taken out of production quite fast to be replaced with the 5cm Pzgr.39 with piercing cap. The projectile body of the 5cm Pzgr is however somewhat longer than the body of the 5cm Pzgr39.
The drivingband is Fes made which is an abriviation for sintered iron drivingbands. The space between the iron grains of the driving band is filled with wax making shure the soft iron and waxed drivingband does not give barrel wear. Also, the usage of scarse copper for drivingbands is avoided.
The projectile weighs 2,06 kg, a complete cartridge weighs 4,05 kg.
Functioning of fuze Bd.Z.5103:
The fuze is made of an externally -lefthand- threaded steel body that fits the thread in the projectile base. The lefthand thread enshurs the fuze is tightened upon firing. In the centerline of the fuze two opposite blind holes are drilled. In the bottom one the tracer element is placed, in the top hole a small alluminium closing cap with a 0,1 mm hole in the center is screwed in top, below that a flat brass firing pin plate with a a firing pin machined at the base. In the lower portion of the hole a cylinder is placed in which a firing cap is placed, fixated with a 0,35 mm dia. brass wire placed in a radial hole through the fuze body and the lower part of the cylinder. The firing cap faces the firing pin. On impact the firing cap is thrown forward by the deceleration, shearing off the wire and throwing the firing cap forward into the firing pin. The flame travels around the (flat plate formed) firing pin and through the tiny hole in the aluminum closure cap of the fuze. As the hole is small , it takes some time to build up enough pressure for the flame to travel through the small hole into the P2 detonator. This is the delay that allows the projectile to pierce the armor before exploding.The flame now reaches the detonator type P2 (Aluminum ring and threaded bush above the fuze), exploding the main charge, exploding the Pentrite (pink) burster charge of the projectile.
The shellcase is steel made and 420mm long. The percussion primer C12 or C12 N.a. is placed in the base of the shellcase. This primer has it’s own black powder magazine to ehsure a fast and even ignition of the main charge in the shellcase. In the German nomenclature the shellcase is named ‘Patronenhulse 6360 St’
The shellcase is filled with 900 grams of tubular powder Digl. R.P (Rohr Pulver), long 310mm with a 3mm diameter and a 1mm hole through.
Below the main powder charge a bag of Nitrocellulose riflepowder 1,5x1,5x0,5mm thick is placed, enshuring the main charge is ignited instantaniously
The penetrating capability of the 5cm PzGr.39 is (perpendicular to the steel target) 96mm at 100 meters, 79mm at 500 meters, 62mm at 1000 meters, and 49mm at 1500 meters.
Groet, DJH
During the Spanish civil war it became soon clear that the 3,7cm Pak 36 gun was insufficiënt in knocking out tanks, later during the invasion of Russia this became rather painfully clear with the appearence of the T-34 to which the Pak 36 had no more effect than scratching the paint. The German army nicknamed the 3,7 Pak 36 ‘Heeresanklopfgerät’ , which translates as the ‘army’s doorknocker’.
As the lack of penetrating power of the Pak 36 was recognized early on, in 1938 Rheinmetall-Borsig had allready started with the development of a more powerfull anti-tank gun; the 5cm Pak 38. This gun had a barrel length of 60 calibres (60x5cm =3m rifled barrel) and was the only gun that was able to knock out a T-34 face on, although at a short distance only. The even heavier armoured KV-1 tank could only be knocked out with a tungsten carbide cored PzGr,40 shell, also at close distance. As it soon became clear that even the Pak 38 would become obsolete soon, the 7,5cm cm Pak 40 was designed and taken into service, and this gun was able to knock out any allied tank at longer ranges.
The Pak 38 was mainly used as a drawn gun, but was also used in the SdKfz 234 Puma armoured car.
The cartridges -although in slightly modified version- were also used in the 5cm BK-5 (Bord Kanone / Aircraft Gun) as used in the Me262 U4 and the Me-410 A1/U4, the difference could be found in the powdercharges in the shellcase and the usage of the C22 Electric ignited primer in the shellcase.
Left, the a 5cm SprGr.Patr.38
The projectile consists of a steel body, with an adjustment ring screwed in top. The AZ.39 fuze is screwed in top of the adjustment ring. This adjustment ring enables a pre-packed explosive charge to be glued in the projectile body with magnesiumkit (kind of predecessor of polyester resign), locking it up with the adjustment ring.
The explosive charge consists of two parts , the top cilinder of 15 grams of Nitropenta, the rest of the cartboard container filled with FP-02 (TNT). In top of this FP-02 charge smoke box No.12 is placed, enabling to observe the impact point of the projctile.
Total weight of the explosive charge is 0,185 kg, of which 0,17 kg is explosives.
Functioning of the AZ-39 impact fuze:
The AZ-39 is an all aluminum fuze. A slider prevents the firing pin from moving downward. The slider is held in place by two radial placed pins that fall in recesses in the side of the slider. These two pins are held inward by a bronze ring shaped interrupted blade spring. Upon firing these two pins are thrown outward (centrifugal force), releasing the slider. A steel ball is placed in an axial hole that is drilled under a 2 degrees outward angle to the top of the fuze. When fired, the acceleration keeps the ball in the lower position, as soon as the velocity is constant, the centrifugal force will make the ball creep the wall of the hole upward until it falls into the hole in the slider. As the slider becomes heavier on this side it will pull the slider outward, releasing the hole for the firing pin. On impact the firing pin is driven into the firing cap of the Duplex detonator, exploding the detonator and the projectile.
The shellcase is steel made and 420mm long. The percussion primer C12 or C12 N.a. is placed in the base of the shellcase. This primer has it’s own black powder magazine to ehshure a fast and even ignition of the main charge in the shellcase. In the German nomenclature the shellcase is named ‘Patronenhulse 6360 St’
The powdercharge in the shellcase consists of a double bag filled with powder. The top bag, containing the main charge is filled with236 grams GU. Bl.P –AO- flaked powder 4x4x0,6mm thick. Below that, a bag containing 30 grams Nitrocellulose rifle powder 1,5x1,5x0,5mm is placed to ensure the main charge in the top bag is ignited instantanoiusly. A single pipe of tubular powder 7mm in diameter with a hole of 5mm through and a length of 345mm is placed in the bag, forcing the bag in the forward position, so the lower bag is forced upon the percussion primer and does not move forward when handled or loaded in the gun, leaving a void between the percussion primer and the bag.
The reason the high explosive shell has a smaller propulsion charge than the armour piercing shell is that the high explosive shell does not need high speed to function, and can therefore do with a much lower speed, lower barrel pressure and as a consequence of that lower barrel wear. The sight of the gun must however be switched from AP to HE as the HE shell has no flat trajectory like the AP shell, but a curved trajectory.
Right, the PzGr.Patr. 39
The projectile is flat based and has a pointed nose, the nose is hardened. There are two ways of manufacturing the projectile, the first is a one piece projectile with a hardened nose, in the second method a nose of better quality alloy steel is friction welded https://www.youtube.com/watch?v=BwC0zXpoZjw
to a lesser quality steel lower body portion. It is called the 5cm Pzgr.39 V. (Verbundgeschoss). This is profitable as the use of expensive alloy steel is highly reduced.
In the base of the projectile an ogive shaped hole is drilled, containing a pressed in charge of 17 grams Nitropenta (NP15 = Nitropenta with 15% of wax). Below this charge a two piece aluminum P2 detonator is placed, and below that the Base fuze (BdZ) 5103 is screwed into the base of the projectile.
On top of the projectile the soft steel piercing cap is soft soldered on top of the projectile. This cap ensures the force of the impact is divided over the entire hardened nose, avoiding it from shattering upon impact. Another advantage of using a piercing cap is that if the projectile hits a target at an agle (f.i. the front hull armour of a T-34 or Sherman tank), the piercing cap will ‘weld’ itself tot he armor and rotate the projectile in a more favourable angle towards perpendicular to the armour during the piercing process. This will improve piercing and reduce the chance of the projectile bouncing off.
The first 5cm PzGr projectiles had no piercing cap and were taken out of production quite fast to be replaced with the 5cm Pzgr.39 with piercing cap. The projectile body of the 5cm Pzgr is however somewhat longer than the body of the 5cm Pzgr39.
The drivingband is Fes made which is an abriviation for sintered iron drivingbands. The space between the iron grains of the driving band is filled with wax making shure the soft iron and waxed drivingband does not give barrel wear. Also, the usage of scarse copper for drivingbands is avoided.
The projectile weighs 2,06 kg, a complete cartridge weighs 4,05 kg.
Functioning of fuze Bd.Z.5103:
The fuze is made of an externally -lefthand- threaded steel body that fits the thread in the projectile base. The lefthand thread enshurs the fuze is tightened upon firing. In the centerline of the fuze two opposite blind holes are drilled. In the bottom one the tracer element is placed, in the top hole a small alluminium closing cap with a 0,1 mm hole in the center is screwed in top, below that a flat brass firing pin plate with a a firing pin machined at the base. In the lower portion of the hole a cylinder is placed in which a firing cap is placed, fixated with a 0,35 mm dia. brass wire placed in a radial hole through the fuze body and the lower part of the cylinder. The firing cap faces the firing pin. On impact the firing cap is thrown forward by the deceleration, shearing off the wire and throwing the firing cap forward into the firing pin. The flame travels around the (flat plate formed) firing pin and through the tiny hole in the aluminum closure cap of the fuze. As the hole is small , it takes some time to build up enough pressure for the flame to travel through the small hole into the P2 detonator. This is the delay that allows the projectile to pierce the armor before exploding.The flame now reaches the detonator type P2 (Aluminum ring and threaded bush above the fuze), exploding the main charge, exploding the Pentrite (pink) burster charge of the projectile.
The shellcase is steel made and 420mm long. The percussion primer C12 or C12 N.a. is placed in the base of the shellcase. This primer has it’s own black powder magazine to ehsure a fast and even ignition of the main charge in the shellcase. In the German nomenclature the shellcase is named ‘Patronenhulse 6360 St’
The shellcase is filled with 900 grams of tubular powder Digl. R.P (Rohr Pulver), long 310mm with a 3mm diameter and a 1mm hole through.
Below the main powder charge a bag of Nitrocellulose riflepowder 1,5x1,5x0,5mm thick is placed, enshuring the main charge is ignited instantaniously
The penetrating capability of the 5cm PzGr.39 is (perpendicular to the steel target) 96mm at 100 meters, 79mm at 500 meters, 62mm at 1000 meters, and 49mm at 1500 meters.
Groet, DJH
Attachments
-
Pict 01 - 5cm SprGr. Patr. 38 & 5cm PzGr. Patr. 39 cutaways.jpg -
Pict 02 - 5cm SprGr. Patr. 38 & 5cm PzGr. Patr. 39 backside.jpg -
Pict 03 - details 5cm SprGr. Patr. 38 & 5cm PzGr. Patr. 39 cutaways.jpg -
Pict 04 - AZ39.jpg -
Pict 05 - Bdz. 5103.JPG -
Pict 06 - 5cm Pak 38 in Tunesie.jpg -
Pict 07 - SdKfz 234 Puma.jpg
Last edited:
