Cutaway model of a highly interesting cartridge; the 20x180R armour piercing cartridge for the Swedish Pansarvärnsgevär fm/42, (abriviation Pvg fm/42) recoilless gun.
The weapon was developed between 1940 and 1942 by Hugo Abramson and Harald Jentzen at the Carl Gustaf Stads GF waeapon factory, and was the first shoulder fired recoiless rifle ever. Approxiametly thousend Pvg fm/42 recoilless guns were delivered to the Swedish army before it was descided that the weapon was obsolete, and a shaped charge was much more effective with a weapon of the same weight.
The Pvg fm/42 however was an important step in the development of one of worlds most famous weapons; the 84mm Carl Gustav recoiless gun, which is often referred to as “hand held artillery”, and is used by a many countries from the 1950’s up to today.
The Pvg fm/42 recoilless gun works according to the Davis recoiless mechanism, where a projectile of a certain weight with a certain speed leaving the barrel equals the force of powdergas (and /or counterweight) with a certain weigt and a certain speed leaving the back of the weapon.
To make this more clear: The Pvg fm/42 AP-T projectile weighs 108 gram (1650 grain) and leaves the barrel with a speed of 950 mtrs/sec (3150 Ft/sec). Say, the gas of the burnt powder charge weighs 75 grams, than the equasion will be 108x950 = 75x1368, so the gas will leave the back of the breech with 1368 mtrs /sec to balance the projectile leaving the barrel.
In this calculation one must consider the force and resistance caused by the lands and grooves that have to be pressed into the driving band; this is nullified by the shape and size of the gas escape holes -forming a certain restriction- in the breech block.
The cartridge consists of a brass shellcasse with a rim at the base. The shellcase has no bottom. Instead a steel ring (pict 03) with a triangular insert (pict 04) housing the firing cap with the magazine is placed in the base of the shellcase, held in placed with three indentations in the side of the shellcase that fall into a groove on the outside of the steel ring.
The spaces around the triangular insert are meant to allow the powder gas to escape the base of the shellcase. In the base of the steel ring a pertinax flange is placed that forms a resistance and enshures all powder in the shellcase is ignited before it breaks apart and allows the powder gas to escape to the rear through the holes in the breech.
The projectile consits of a hardened steel shot with a hole drilled in the base for the tracer composition.
The armour penetration of the Pvg fm/42 was impressive; 40mm at 100 meters on a vertical steel plate.
The Pvg fm/42 weighed 11,7 kg (25Lb) only, a big advantage over other 20mm anti tank rifles like the 20x138B solothurm and the Lathi anti-tank guns that were heavy and were -preferably- carried by two persons, but were most often placed on a small trolley or placed on light vehicles.
Against tanks at the start of WW2 it was an effective weapon, but during WW2 tank armour was getting thicker, sloped, and used extra spaced armour plates (Schurtze) that rendered the weapon ineffective.
For the Pvg fm/42 a high explosvie cartridge was available, however I have no info on that cartridge.
An interesting detail (pict 05): The AP-T projectile used on the 20x180R cartrige is the same AP-T projectile used on the 20x110G shellcase for the HS-404 automatic cannon. The projectiles are manufactured by the SKF ball bearing factory.
A disadvantage of firing this weapon is that it does not go unnoticed as one can see on this impressive movie on you tube… turn the volume open fully and enjoy;
Carl Gustav 20mm recoilless rifle at O.F.A.S.T.S. 2010 - YouTube
Another interesting movie, describing the weapon:
Carl Gustav m/42: A 20mm Recoilless Antitank Rifle - YouTube
Regards, DJH
The weapon was developed between 1940 and 1942 by Hugo Abramson and Harald Jentzen at the Carl Gustaf Stads GF waeapon factory, and was the first shoulder fired recoiless rifle ever. Approxiametly thousend Pvg fm/42 recoilless guns were delivered to the Swedish army before it was descided that the weapon was obsolete, and a shaped charge was much more effective with a weapon of the same weight.
The Pvg fm/42 however was an important step in the development of one of worlds most famous weapons; the 84mm Carl Gustav recoiless gun, which is often referred to as “hand held artillery”, and is used by a many countries from the 1950’s up to today.
The Pvg fm/42 recoilless gun works according to the Davis recoiless mechanism, where a projectile of a certain weight with a certain speed leaving the barrel equals the force of powdergas (and /or counterweight) with a certain weigt and a certain speed leaving the back of the weapon.
To make this more clear: The Pvg fm/42 AP-T projectile weighs 108 gram (1650 grain) and leaves the barrel with a speed of 950 mtrs/sec (3150 Ft/sec). Say, the gas of the burnt powder charge weighs 75 grams, than the equasion will be 108x950 = 75x1368, so the gas will leave the back of the breech with 1368 mtrs /sec to balance the projectile leaving the barrel.
In this calculation one must consider the force and resistance caused by the lands and grooves that have to be pressed into the driving band; this is nullified by the shape and size of the gas escape holes -forming a certain restriction- in the breech block.
The cartridge consists of a brass shellcasse with a rim at the base. The shellcase has no bottom. Instead a steel ring (pict 03) with a triangular insert (pict 04) housing the firing cap with the magazine is placed in the base of the shellcase, held in placed with three indentations in the side of the shellcase that fall into a groove on the outside of the steel ring.
The spaces around the triangular insert are meant to allow the powder gas to escape the base of the shellcase. In the base of the steel ring a pertinax flange is placed that forms a resistance and enshures all powder in the shellcase is ignited before it breaks apart and allows the powder gas to escape to the rear through the holes in the breech.
The projectile consits of a hardened steel shot with a hole drilled in the base for the tracer composition.
The armour penetration of the Pvg fm/42 was impressive; 40mm at 100 meters on a vertical steel plate.
The Pvg fm/42 weighed 11,7 kg (25Lb) only, a big advantage over other 20mm anti tank rifles like the 20x138B solothurm and the Lathi anti-tank guns that were heavy and were -preferably- carried by two persons, but were most often placed on a small trolley or placed on light vehicles.
Against tanks at the start of WW2 it was an effective weapon, but during WW2 tank armour was getting thicker, sloped, and used extra spaced armour plates (Schurtze) that rendered the weapon ineffective.
For the Pvg fm/42 a high explosvie cartridge was available, however I have no info on that cartridge.
An interesting detail (pict 05): The AP-T projectile used on the 20x180R cartrige is the same AP-T projectile used on the 20x110G shellcase for the HS-404 automatic cannon. The projectiles are manufactured by the SKF ball bearing factory.
A disadvantage of firing this weapon is that it does not go unnoticed as one can see on this impressive movie on you tube… turn the volume open fully and enjoy;
Carl Gustav 20mm recoilless rifle at O.F.A.S.T.S. 2010 - YouTube
Another interesting movie, describing the weapon:
Carl Gustav m/42: A 20mm Recoilless Antitank Rifle - YouTube
Regards, DJH
