pzgr40
Well-Known Member
Cutaway models of several 20x139 shells.
It was originally designed by Hispano-Suiza in the 1950s for their HS 820 cannon, which they saw as the natural successor to the HS 804. Hispano-Suiza was taken over by Oerlikon in 1971, after which the HS 820 was renamed the Oerlikon KAD. The cartridge has been successful, mainly because of its use in the popular Rheinmetall Rh 202 cannon. It is also chambered in the GIAT F2 / 20M693, which is made in South Africa as the Vektor G1-2. These guns have seen various uses, as naval and land-based AA, light AFV armament and in helicopters.
The shells are produced by a number of countries; Germany, Switzerland, Netherlands , Italy, South Africa , Norway, France , USA.
Functioning of the mechanical self destruct mechanism disc,as used in projectiles of type 2, 3, 5, 6:
The disc is placed below a spring tensioned ring that exactly fits the hole in the centre of the disc. The ring wants to push the firing pin down by its disc into the detonator, however the ring is held in upward position by the release (R), which prevents it from moving down. The release has a hook on one end (green arrow) which rotates around a pivot pin (P2). It is held in position by a banana shaped hook which pivots around a pin (P1). It hooks in the release (green arrow). The banana shaped hook is held in position by a leaf spring (blue arrow). On firing, the weight (W) is thrown outward, enabeling the leaf spring to move outward. As long as the centrifugal force is large enough and the weight (W) is thrown outward, the two parts hook into each other (green arrow). As soon as the centrifugal force decreases, the rotation spring surrounding the pivot (P1) starts to push the weight (W) inward, releasing the hooks (green arrow). The release (R) can now move outward, enabeling the ring to pass through the centre hole and push the firing pin down into self destruct.
Type 1:
20x139 High explosive incendiary tracer self destruct (HEI-T-SD) MP (Multi purpose) DM91
The projectile has a steel body with a screwed in aluminium nose piece. The upper part of the body and the nose piece are filled with thermite, the lower part of the body is filled with an explosive charge.
The projectile has a tracer with a pyrotechnical self destruct mechanism, which ignites the explosive charge if the target is missed.
The projectile has no safety features and is ignited by impact energy. The explosive charge is ignited by the thermite charge. The force to ignite the cartridge must be conciderable (impact) , dropping it or a loading mishandling cannot ignite the projectile.
This projectile has been manufactured by Ra (Raufoss), and as far as I know the projectile is of Norwegian (Raufoss) design.
Type 2:
20x139 High explosive incendiary- tracer -Self destruct (HEI-T/SD), fuzed with the AZZ M594A1 (Anschlag Zerlege Zunder / Impact self destruct fuze).
The projectile body is made of mild steel, a hole has been drilled in the base to house the tracer element.
Functioning of the fuze AZZ M594A1:
The fuze has three safetys;
-The ball housing the detonator is out of line with the firing pin.
-The ball is fixated by a red copper U shaped clamp that only opens on rotation.
-A spiral wound metal tape just below the ball that prevents the firing pin from moving forward into the detonator, and only unwinds after firing.
On firing, the rotation bend open the copper clamp, enabeling the ball to move freely. The force of the rotation will throw the heavy part of the ball outward, thereby turning the detonator channel in line with the centerline of the projectile. At the same moment the spiral wound metal tape unwinds, releasing the firing pin and enabeling it to reach the detonator. The firing pin is made up of a needle with a disc shaped part just below the top. On this disc, a ring rests which is pushed down by the central spring, surrounding the stem of the hammer pin above the firing pin. The firing pin is prevented from moving down into the detonator by the Mechanical self destruct disc, up to the moment where the ring under the spring is enabled to move down through the disc, pushing the firing pin into the detonator and self destruct occurs.
Weight complete cartridge: 0,317 kg.
Weight of projectile: 0,120 kg.
V0.: 1045 mtrs/sec.
Length of complete cartridge: 213 mm.
The cartridge has been manufactured in The Netherlands by the NWM
Type 3:
20x139 DM101A1 High explosive incendiary shell with a base fuze (HEI-T-SD). The projectile is fuzed with the DM771B1 self destruct base fuze.
The projectile has a mild steel body, filled with a 4,1grams explosive incendiary charge Hexal (Hexogen/aluminium). A small -1,7 grams- incendiary Zirconium/Hafnium (black) charge on top of the explosive charge that increases the blast working of the explosive charge. A 3,4 grams thermit incendiary charge (red) is placed in an aluminium ballistic cap on top of the projectile.
Functioning of the fuze DM77B1: The fuze has three safetys;
-The ball housing the detonator is out of line with the firing pin.
-The ball is fixated by a red copper U shaped clamp that only opens on rotation.
-A spiral wound metal tape just below the ball that prevents the firing pin from moving forward into the detonator, and only unwinds after firing.
On firing, the rotation bend open the copper clamp, enabeling the ball to move freely. The force of the rotation will throw the heavy part of the ball outward, thereby turning the detonator channel in line with the centerline of the projectile. At the same moment the spiral wound metal tape unwinds, releasing the firing pin and enabeling it to reach the detonator. The firing pin is made up of a needle with a cylindrical hammer piece. When armed the firing pin is kept away from the detonator by a weak spring. Below the hammer piece, the mechanical self destruct mechanism disc is placed, facing downward. Below this disc, a spring is placed that pushes the firing pin with the hammer piece upward on self destruct.
Weight complete cartridge: 0,317 kg.
Weight of projectile: 0,120 kg.
V0.: 1055 mtrs/sec.
Self destruct at appr. 2200 mtrs
Length of complete cartridge: 212 mm.
The cartridge has been manufactured in Germany
Type 4:
20x139 HEI , type designation unknown, of Swiss design. The original design of the 20x139 goes back to the 50s of the last century. The Hispano Suiza factory designed and produced the 20x139 for the HS-820 gun as a replacement for the 20x110 HS804, the Oerlikon factory designed and produced a comparable cartridge, the 20x129. When the Hispano factory was bought up by the Oerlikon company in 1971, the Hispano s 20x139 cartridge was pushed out in favour of the 20x129, allthough this type of cartridge was much less popular than the 20x139. Most countrys using the 20x139 than took up the production of cartridges themselves. It can be clearly observed that the mechanical self destruct fuzes internal parts and functioning are exactly the same as the Hispanos 20x110 AAA cartridge.
Functioning of the fuze:
Inside the fuze body, an aluminium self destruct piston is placed, housing four steel balls and the a spring that wants to push the piston down. The piston rests on two brass chamfered centrifugal safety pins, placed in a radial position compared to the fuze body and whom prevent the piston from moving down and the firing pin from reaching the detonator. The lower part of the firing pin has a disc shaped part which is positioned under the piston; on impact the firing pin can move down, on self destruct the firing pin is pushed down by the piston, pushing the disc of the firing pin down.
A thin walled brass cylinder chamfered on the inside upper edge- is placed around the piston.
Upon firing, the set back force pushes all parts downward, preventing the fuze from arming. At a safe distance from the gun the centrifugal force throws all parts outward. The chamfered edges of the two brass pins climb the chamfered edge on the inside of the brass detonator housing, pushing the brass cylinder upward and releasing the aluminium piston. This piston however is locked in position by the four balls thrown outward into the chamfered edge inside the brass cylinder. The firing pin is now free floating, on impact it is hammered into the detonator. If no target is hit, a moment will occur where the force of the spring inside the piston is larger than the locking force of the four balls in the chamfered edge of the brass cylinder. The balls will now be pushed back into the piston, allowing the piston to move down, pushing the firing pin into the detonator by means of the disc on the firing pin.
Type 5:
20x139 High explosive incendiary - tracer (HEI-T) DM51A1, fuzed with the impactfuze DM131A1.
The projectile has a mild steel body DM 1027and a hole drilled in the base that houses a tracer. The Incendiary-explosive charge of mixture 891 has been pressed in the body.
Functioning of the fuze:
After firing, the sprial wound metal tape unwinds, enabeling the firing pin to reach the detonator on impact. A mechanical self destruct mechanism disc is placed above this spring, destroying the projectile if no target is hit after appr. 7-11 sec. of flight.
Weight complete cartridge: 0,317 kg.
Weight of projectile: 0,122 kg.
V0.: 1045 mtrs/sec.
Length of complete cartridge: 212 mm.
The cartridge has been manufactured in Germany.
Type 6:
German 20x139 cartridge with the DM41 HEI-T projectile fuzed with the AZZ-E4 impact fuze with mechanical self-destruct mechanism.
The body is made of mild steel, and it has a tracer in the base.
Functioning of the AZZ E4
The fuze has three safetys;
-The ball housing the detonator is out of line with the firing pin.
-The ball is fixated by a red copper U shaped clamp that only opens on rotation.
-A spiral wound metal tape just below the ball that prevents the firing pin from moving forward into the detonator, and only unwinds after firing.
On firing, the rotation bend open the copper clamp, enabeling the ball to move freely. The force of the rotation will throw the heavy part of the ball outward, thereby turning the detonator channel in line with the centerline of the projectile. At the same moment the spiral wound metal tape unwinds, releasing the firing pin and enabeling it to reach the detonator. The firing pin is made up of a needle with a disc shaped part just below the top. On this disc, a ring rests which is pushed down by the central spring, surrounding the stem of the hammer pin above the firing pin. The firing pin is prevented from moving down into the detonator by the Mechanical self-destruct disc, up to the moment where the ring under the spring is enabled to move down through the disc, pushing the firing pin into the detonator and self-destruct occurs.
Type 7:
20x139 cartridge with a HEI-T-SD projectile of unknown origin. Upon firing, the ball housing the detonator is out of line with the firing pin.
The ball is fixated by a red copper U shaped clamp that keeps the ball fixated in one position.
Upon firing, the rotation bend open the copper clamp, enabeling the ball to move freely. The force of the rotation will throw the heavy part of the ball outward, thereby turning the detonator channel in line with the centerline of the projectile. The firing pin is made up of a flanged pin which rests upon the shoulder of a hole in top. A sheet metal cap is crimped over the nose to prevent the firing pin from falling out. Upon impact, the firing pin is hammered inward, ripping off at the flange, moving down into the firing cap of the detonator in the ball. This will detonate the projectile. If no target is hit, the tracer burning up will ignite the tracer self-destruct.
I have no idea what country made this projectile or what its designation is.
The build-up of the projectile looks quite American to me, it bears great resemblance with the M55A1 fuze of the 20x102 vulcan HE projectiles. The US army has used the HS-820 gun.
If anyone has more info, please let me know.
Type 8:
Swiss 20x139 cartridge with a HEI (High Explosive Incendiary) projectile, with the Swiss designation MLA (without tracer MSA).
The projectile body is made of mild steel with a 3 seconds tracer in the base. The explosive filler is hexal.
The nose fuze is of the mechanical self-destruct type. The b fuze has a spring loaded firing pin housing, held in upward position by a wound up brass tape that shoulders over a rim on top of the brass inner housing.
The upper part of the firing pin housing has four radial holes with a small steel ball in the hole. A brass ring with a chamfered edge is placed over the firing pin housing iwo the balls. Upon firing, the balls are swung outward (centrifugal force), and as the brass rings chamfer is a little lower than the radial centreline of the balls, the balls pull the firing pin housing just a fraction upward, tensioning the firing spring even more. However, the brass tape is now released to unroll and release the firing pin housing. As long as the force of the four balls pressing outward in the chamfered edge of the ring is greater than the downward force of the firing pin spring, the firing pin is kept in upward position.
If a target is hit, the firing pin is hammered inward, pushing the firing pin into the duplex detonator (red), exploding the projectile.
If no target is hit, the force of the firing pin spring will overcome the force of the four balls in the groove, pushing the balls back into the holes in the firing pin housing, allowing the firing pin to be pushed in the firing cap by the firing pin spring, initiating the self-destruct function.
Type 9:
German Diehl manufactured 20 x 139mm DE 111 APERS Shrapnel round.
DE stands for "Deutsches Erprobungsmodell" , meaning "round under evaluation
This round has a striker in the base, pushed forward in the firing cap (red) upon firing. The firing cap ignites the delay element (yellow) above the firing cap (delay is about 40ms) . Above this delay charge an ejection tube with an extension tube on top is placed, filled with a number of small tungsten balls. The lower extension tube has a chamber housing a powder charge which launches both extension tubes and the load off balls forward upon ignition of the powder charge. All this is topped with an aluminum ballistic cap that will be pushed off over a weakened rim by the action of the previously mentioned parts.
The cartridge has not been taken into active service.
Type 10:
Swiss 20x139 cartridge SAP-HEI, called PSA (tracer type is called PLA). The projectile is Semi Armour Piercing High Explosive Incendiary). It exists of a steel body with the nose piece hardened. On top an aluminium ballistic cap is crimped. In the base a hole is drilled, housing the explosive charge (blue). In the base of the projectile the base fuze with self-destruct mechanism is screwed.
The base fuze has a spring loaded firing pin housing, held in backward position by a wound up brass tape that shoulders over a rim in the aluminium housing.
The lower part of the firing pin housing has four radial holes with a small steel ball in the hole. A brass ring with a chamfered ring is placed over the firing pin housing iwo the balls. Upon firing, the balls are swung outward (centrifugal force), and as the brass rings chamfer is a little lower than the radial centreline of the balls, the balls pull the firing pin housing just a fraction downward , tensioning the firing spring even more. However, the brass tape is now released to unroll and release the firing pin housing. As long as the force of the four balls pressing outward in the chamfered edge of the ring is greater than the upward force of the firing pin spring, the firing pin is kept in backward position.
If a target is hit, the firing pin is swept forward by the inertia, the delay is formed by the time the balls are pushed back inward and the firing pin moving into the duplex detonator (red).
If no target is hit, the force of the firing pin spring will overcome the force of the four balls in the groove, pushing the balls back into the holes in the firing pin housing, initiating the self-destruct function.
I have no info about the penetration capabilities.
Type 11:
20x139 API -T (Armour Piercing Incendiary Tracer). A cartridge of unknown origin. It has a mild steel body with a hardened steel nose. It is most probably filled with a hexal mix with a high aluminium content. Upon impact , the heat and shockwave will ignite the main charge during penetration.
It is not known what the penetration capability of the projectile is.
The cartridge resembles the WW2 British 20x110 Hispano-Suiza API (red body, white nose) in functioning.
Type 12:
20x139 Armour piercing incendiary tracer DM43 (API-T).
An aluminium projectile body, housing a tungsten carbide core. The nose of the projectile is filled with a MX-71 magnesium incendiary / flash charge which shows the point of impact on the target.
Weight complete cartridge: 0,31 kg.
Weight of projectile: 0,111 kg.
V0.: 1100 mtrs/sec.
Penetration @ 1000 mtrs: 32 mm at 90 degr, 24 mm at 60 degr, 8 mm at 30degr.
Length of complete cartridge: 212 mm.
The cartridge has been manufactured in Germany.
Type 13:
20x139 Armour piercing discarding sabot tracer DM63 (APDS-T)
The projectile is made up of three main components;
-the aluminium base, housing the driving belt and the core
-the tungsten carbide core with an aluminium ballistic cap
-the nylon sabot.
After leaving the barrel, the sabot rips open over four weakening lines and is blown away.
An endless spring fixates the tungsten core in the aluminium base, only after firing will the centrifugal force widen the diameter of the spring enabeling the core to seperate from the aluminium base piece.
Weight complete cartridge: 0,31 kg.
Weight of projectile: 0,108 kg.
V0.: 1150 mtrs/sec.
Penetration: 35mm armour steel plate at 1000 mtrs. @45 degrees
Length of complete cartridge: 212 mm.
The cartridge has been manufactured in Holland (NWM).
Type 14:
Experimental 20x139 Armour piercing discarding sabot tracer (APDS-T)
The projectile is made up of three main components;
-the aluminium base, housing the driving belt and the core
-the tungsten carbide core with an aluminium ballistic cap
-the nylon sabot.
After leaving the barrel, the sabot rips open over four weakening lines and is blown away.
An endless spring fixates the tungsten core in the aluminium base, only after firing will the centrifugal force widen the diameter of the spring enabeling the core to seperate from the aluminium base piece.
The cartridge has been manufactured in Holland (NWM).
The cartridge differs from the DM63 in the length of the aluminium piercing cap on top of the tungsten penetrator. The cartridge has not been taken into service.
The cutaway model is a factory cutaway model.
An interesting piece of film, showing the gun in action can be found here:
http://www.youtube.com/watch?v=Rs43VkMWnEk&mode=related&search=
Regards, DJH
It was originally designed by Hispano-Suiza in the 1950s for their HS 820 cannon, which they saw as the natural successor to the HS 804. Hispano-Suiza was taken over by Oerlikon in 1971, after which the HS 820 was renamed the Oerlikon KAD. The cartridge has been successful, mainly because of its use in the popular Rheinmetall Rh 202 cannon. It is also chambered in the GIAT F2 / 20M693, which is made in South Africa as the Vektor G1-2. These guns have seen various uses, as naval and land-based AA, light AFV armament and in helicopters.
The shells are produced by a number of countries; Germany, Switzerland, Netherlands , Italy, South Africa , Norway, France , USA.
Functioning of the mechanical self destruct mechanism disc,as used in projectiles of type 2, 3, 5, 6:
The disc is placed below a spring tensioned ring that exactly fits the hole in the centre of the disc. The ring wants to push the firing pin down by its disc into the detonator, however the ring is held in upward position by the release (R), which prevents it from moving down. The release has a hook on one end (green arrow) which rotates around a pivot pin (P2). It is held in position by a banana shaped hook which pivots around a pin (P1). It hooks in the release (green arrow). The banana shaped hook is held in position by a leaf spring (blue arrow). On firing, the weight (W) is thrown outward, enabeling the leaf spring to move outward. As long as the centrifugal force is large enough and the weight (W) is thrown outward, the two parts hook into each other (green arrow). As soon as the centrifugal force decreases, the rotation spring surrounding the pivot (P1) starts to push the weight (W) inward, releasing the hooks (green arrow). The release (R) can now move outward, enabeling the ring to pass through the centre hole and push the firing pin down into self destruct.
Type 1:
20x139 High explosive incendiary tracer self destruct (HEI-T-SD) MP (Multi purpose) DM91
The projectile has a steel body with a screwed in aluminium nose piece. The upper part of the body and the nose piece are filled with thermite, the lower part of the body is filled with an explosive charge.
The projectile has a tracer with a pyrotechnical self destruct mechanism, which ignites the explosive charge if the target is missed.
The projectile has no safety features and is ignited by impact energy. The explosive charge is ignited by the thermite charge. The force to ignite the cartridge must be conciderable (impact) , dropping it or a loading mishandling cannot ignite the projectile.
This projectile has been manufactured by Ra (Raufoss), and as far as I know the projectile is of Norwegian (Raufoss) design.
Type 2:
20x139 High explosive incendiary- tracer -Self destruct (HEI-T/SD), fuzed with the AZZ M594A1 (Anschlag Zerlege Zunder / Impact self destruct fuze).
The projectile body is made of mild steel, a hole has been drilled in the base to house the tracer element.
Functioning of the fuze AZZ M594A1:
The fuze has three safetys;
-The ball housing the detonator is out of line with the firing pin.
-The ball is fixated by a red copper U shaped clamp that only opens on rotation.
-A spiral wound metal tape just below the ball that prevents the firing pin from moving forward into the detonator, and only unwinds after firing.
On firing, the rotation bend open the copper clamp, enabeling the ball to move freely. The force of the rotation will throw the heavy part of the ball outward, thereby turning the detonator channel in line with the centerline of the projectile. At the same moment the spiral wound metal tape unwinds, releasing the firing pin and enabeling it to reach the detonator. The firing pin is made up of a needle with a disc shaped part just below the top. On this disc, a ring rests which is pushed down by the central spring, surrounding the stem of the hammer pin above the firing pin. The firing pin is prevented from moving down into the detonator by the Mechanical self destruct disc, up to the moment where the ring under the spring is enabled to move down through the disc, pushing the firing pin into the detonator and self destruct occurs.
Weight complete cartridge: 0,317 kg.
Weight of projectile: 0,120 kg.
V0.: 1045 mtrs/sec.
Length of complete cartridge: 213 mm.
The cartridge has been manufactured in The Netherlands by the NWM
Type 3:
20x139 DM101A1 High explosive incendiary shell with a base fuze (HEI-T-SD). The projectile is fuzed with the DM771B1 self destruct base fuze.
The projectile has a mild steel body, filled with a 4,1grams explosive incendiary charge Hexal (Hexogen/aluminium). A small -1,7 grams- incendiary Zirconium/Hafnium (black) charge on top of the explosive charge that increases the blast working of the explosive charge. A 3,4 grams thermit incendiary charge (red) is placed in an aluminium ballistic cap on top of the projectile.
Functioning of the fuze DM77B1: The fuze has three safetys;
-The ball housing the detonator is out of line with the firing pin.
-The ball is fixated by a red copper U shaped clamp that only opens on rotation.
-A spiral wound metal tape just below the ball that prevents the firing pin from moving forward into the detonator, and only unwinds after firing.
On firing, the rotation bend open the copper clamp, enabeling the ball to move freely. The force of the rotation will throw the heavy part of the ball outward, thereby turning the detonator channel in line with the centerline of the projectile. At the same moment the spiral wound metal tape unwinds, releasing the firing pin and enabeling it to reach the detonator. The firing pin is made up of a needle with a cylindrical hammer piece. When armed the firing pin is kept away from the detonator by a weak spring. Below the hammer piece, the mechanical self destruct mechanism disc is placed, facing downward. Below this disc, a spring is placed that pushes the firing pin with the hammer piece upward on self destruct.
Weight complete cartridge: 0,317 kg.
Weight of projectile: 0,120 kg.
V0.: 1055 mtrs/sec.
Self destruct at appr. 2200 mtrs
Length of complete cartridge: 212 mm.
The cartridge has been manufactured in Germany
Type 4:
20x139 HEI , type designation unknown, of Swiss design. The original design of the 20x139 goes back to the 50s of the last century. The Hispano Suiza factory designed and produced the 20x139 for the HS-820 gun as a replacement for the 20x110 HS804, the Oerlikon factory designed and produced a comparable cartridge, the 20x129. When the Hispano factory was bought up by the Oerlikon company in 1971, the Hispano s 20x139 cartridge was pushed out in favour of the 20x129, allthough this type of cartridge was much less popular than the 20x139. Most countrys using the 20x139 than took up the production of cartridges themselves. It can be clearly observed that the mechanical self destruct fuzes internal parts and functioning are exactly the same as the Hispanos 20x110 AAA cartridge.
Functioning of the fuze:
Inside the fuze body, an aluminium self destruct piston is placed, housing four steel balls and the a spring that wants to push the piston down. The piston rests on two brass chamfered centrifugal safety pins, placed in a radial position compared to the fuze body and whom prevent the piston from moving down and the firing pin from reaching the detonator. The lower part of the firing pin has a disc shaped part which is positioned under the piston; on impact the firing pin can move down, on self destruct the firing pin is pushed down by the piston, pushing the disc of the firing pin down.
A thin walled brass cylinder chamfered on the inside upper edge- is placed around the piston.
Upon firing, the set back force pushes all parts downward, preventing the fuze from arming. At a safe distance from the gun the centrifugal force throws all parts outward. The chamfered edges of the two brass pins climb the chamfered edge on the inside of the brass detonator housing, pushing the brass cylinder upward and releasing the aluminium piston. This piston however is locked in position by the four balls thrown outward into the chamfered edge inside the brass cylinder. The firing pin is now free floating, on impact it is hammered into the detonator. If no target is hit, a moment will occur where the force of the spring inside the piston is larger than the locking force of the four balls in the chamfered edge of the brass cylinder. The balls will now be pushed back into the piston, allowing the piston to move down, pushing the firing pin into the detonator by means of the disc on the firing pin.
Type 5:
20x139 High explosive incendiary - tracer (HEI-T) DM51A1, fuzed with the impactfuze DM131A1.
The projectile has a mild steel body DM 1027and a hole drilled in the base that houses a tracer. The Incendiary-explosive charge of mixture 891 has been pressed in the body.
Functioning of the fuze:
After firing, the sprial wound metal tape unwinds, enabeling the firing pin to reach the detonator on impact. A mechanical self destruct mechanism disc is placed above this spring, destroying the projectile if no target is hit after appr. 7-11 sec. of flight.
Weight complete cartridge: 0,317 kg.
Weight of projectile: 0,122 kg.
V0.: 1045 mtrs/sec.
Length of complete cartridge: 212 mm.
The cartridge has been manufactured in Germany.
Type 6:
German 20x139 cartridge with the DM41 HEI-T projectile fuzed with the AZZ-E4 impact fuze with mechanical self-destruct mechanism.
The body is made of mild steel, and it has a tracer in the base.
Functioning of the AZZ E4
The fuze has three safetys;
-The ball housing the detonator is out of line with the firing pin.
-The ball is fixated by a red copper U shaped clamp that only opens on rotation.
-A spiral wound metal tape just below the ball that prevents the firing pin from moving forward into the detonator, and only unwinds after firing.
On firing, the rotation bend open the copper clamp, enabeling the ball to move freely. The force of the rotation will throw the heavy part of the ball outward, thereby turning the detonator channel in line with the centerline of the projectile. At the same moment the spiral wound metal tape unwinds, releasing the firing pin and enabeling it to reach the detonator. The firing pin is made up of a needle with a disc shaped part just below the top. On this disc, a ring rests which is pushed down by the central spring, surrounding the stem of the hammer pin above the firing pin. The firing pin is prevented from moving down into the detonator by the Mechanical self-destruct disc, up to the moment where the ring under the spring is enabled to move down through the disc, pushing the firing pin into the detonator and self-destruct occurs.
Type 7:
20x139 cartridge with a HEI-T-SD projectile of unknown origin. Upon firing, the ball housing the detonator is out of line with the firing pin.
The ball is fixated by a red copper U shaped clamp that keeps the ball fixated in one position.
Upon firing, the rotation bend open the copper clamp, enabeling the ball to move freely. The force of the rotation will throw the heavy part of the ball outward, thereby turning the detonator channel in line with the centerline of the projectile. The firing pin is made up of a flanged pin which rests upon the shoulder of a hole in top. A sheet metal cap is crimped over the nose to prevent the firing pin from falling out. Upon impact, the firing pin is hammered inward, ripping off at the flange, moving down into the firing cap of the detonator in the ball. This will detonate the projectile. If no target is hit, the tracer burning up will ignite the tracer self-destruct.
I have no idea what country made this projectile or what its designation is.
The build-up of the projectile looks quite American to me, it bears great resemblance with the M55A1 fuze of the 20x102 vulcan HE projectiles. The US army has used the HS-820 gun.
If anyone has more info, please let me know.
Type 8:
Swiss 20x139 cartridge with a HEI (High Explosive Incendiary) projectile, with the Swiss designation MLA (without tracer MSA).
The projectile body is made of mild steel with a 3 seconds tracer in the base. The explosive filler is hexal.
The nose fuze is of the mechanical self-destruct type. The b fuze has a spring loaded firing pin housing, held in upward position by a wound up brass tape that shoulders over a rim on top of the brass inner housing.
The upper part of the firing pin housing has four radial holes with a small steel ball in the hole. A brass ring with a chamfered edge is placed over the firing pin housing iwo the balls. Upon firing, the balls are swung outward (centrifugal force), and as the brass rings chamfer is a little lower than the radial centreline of the balls, the balls pull the firing pin housing just a fraction upward, tensioning the firing spring even more. However, the brass tape is now released to unroll and release the firing pin housing. As long as the force of the four balls pressing outward in the chamfered edge of the ring is greater than the downward force of the firing pin spring, the firing pin is kept in upward position.
If a target is hit, the firing pin is hammered inward, pushing the firing pin into the duplex detonator (red), exploding the projectile.
If no target is hit, the force of the firing pin spring will overcome the force of the four balls in the groove, pushing the balls back into the holes in the firing pin housing, allowing the firing pin to be pushed in the firing cap by the firing pin spring, initiating the self-destruct function.
Type 9:
German Diehl manufactured 20 x 139mm DE 111 APERS Shrapnel round.
DE stands for "Deutsches Erprobungsmodell" , meaning "round under evaluation
This round has a striker in the base, pushed forward in the firing cap (red) upon firing. The firing cap ignites the delay element (yellow) above the firing cap (delay is about 40ms) . Above this delay charge an ejection tube with an extension tube on top is placed, filled with a number of small tungsten balls. The lower extension tube has a chamber housing a powder charge which launches both extension tubes and the load off balls forward upon ignition of the powder charge. All this is topped with an aluminum ballistic cap that will be pushed off over a weakened rim by the action of the previously mentioned parts.
The cartridge has not been taken into active service.
Type 10:
Swiss 20x139 cartridge SAP-HEI, called PSA (tracer type is called PLA). The projectile is Semi Armour Piercing High Explosive Incendiary). It exists of a steel body with the nose piece hardened. On top an aluminium ballistic cap is crimped. In the base a hole is drilled, housing the explosive charge (blue). In the base of the projectile the base fuze with self-destruct mechanism is screwed.
The base fuze has a spring loaded firing pin housing, held in backward position by a wound up brass tape that shoulders over a rim in the aluminium housing.
The lower part of the firing pin housing has four radial holes with a small steel ball in the hole. A brass ring with a chamfered ring is placed over the firing pin housing iwo the balls. Upon firing, the balls are swung outward (centrifugal force), and as the brass rings chamfer is a little lower than the radial centreline of the balls, the balls pull the firing pin housing just a fraction downward , tensioning the firing spring even more. However, the brass tape is now released to unroll and release the firing pin housing. As long as the force of the four balls pressing outward in the chamfered edge of the ring is greater than the upward force of the firing pin spring, the firing pin is kept in backward position.
If a target is hit, the firing pin is swept forward by the inertia, the delay is formed by the time the balls are pushed back inward and the firing pin moving into the duplex detonator (red).
If no target is hit, the force of the firing pin spring will overcome the force of the four balls in the groove, pushing the balls back into the holes in the firing pin housing, initiating the self-destruct function.
I have no info about the penetration capabilities.
Type 11:
20x139 API -T (Armour Piercing Incendiary Tracer). A cartridge of unknown origin. It has a mild steel body with a hardened steel nose. It is most probably filled with a hexal mix with a high aluminium content. Upon impact , the heat and shockwave will ignite the main charge during penetration.
It is not known what the penetration capability of the projectile is.
The cartridge resembles the WW2 British 20x110 Hispano-Suiza API (red body, white nose) in functioning.
Type 12:
20x139 Armour piercing incendiary tracer DM43 (API-T).
An aluminium projectile body, housing a tungsten carbide core. The nose of the projectile is filled with a MX-71 magnesium incendiary / flash charge which shows the point of impact on the target.
Weight complete cartridge: 0,31 kg.
Weight of projectile: 0,111 kg.
V0.: 1100 mtrs/sec.
Penetration @ 1000 mtrs: 32 mm at 90 degr, 24 mm at 60 degr, 8 mm at 30degr.
Length of complete cartridge: 212 mm.
The cartridge has been manufactured in Germany.
Type 13:
20x139 Armour piercing discarding sabot tracer DM63 (APDS-T)
The projectile is made up of three main components;
-the aluminium base, housing the driving belt and the core
-the tungsten carbide core with an aluminium ballistic cap
-the nylon sabot.
After leaving the barrel, the sabot rips open over four weakening lines and is blown away.
An endless spring fixates the tungsten core in the aluminium base, only after firing will the centrifugal force widen the diameter of the spring enabeling the core to seperate from the aluminium base piece.
Weight complete cartridge: 0,31 kg.
Weight of projectile: 0,108 kg.
V0.: 1150 mtrs/sec.
Penetration: 35mm armour steel plate at 1000 mtrs. @45 degrees
Length of complete cartridge: 212 mm.
The cartridge has been manufactured in Holland (NWM).
Type 14:
Experimental 20x139 Armour piercing discarding sabot tracer (APDS-T)
The projectile is made up of three main components;
-the aluminium base, housing the driving belt and the core
-the tungsten carbide core with an aluminium ballistic cap
-the nylon sabot.
After leaving the barrel, the sabot rips open over four weakening lines and is blown away.
An endless spring fixates the tungsten core in the aluminium base, only after firing will the centrifugal force widen the diameter of the spring enabeling the core to seperate from the aluminium base piece.
The cartridge has been manufactured in Holland (NWM).
The cartridge differs from the DM63 in the length of the aluminium piercing cap on top of the tungsten penetrator. The cartridge has not been taken into service.
The cutaway model is a factory cutaway model.
An interesting piece of film, showing the gun in action can be found here:
http://www.youtube.com/watch?v=Rs43VkMWnEk&mode=related&search=
Regards, DJH
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