I've posted a few of these on the forum before so thought it was time to pull them together for a family photo.
The photograph shows a selection of rounds which with one exception started life as larger calibre and were necked down for various reasons.
From left to right:
The Bofors 20 x 311/SR is a necked down Bofors 40 x 411/SR anti aircraft round. The cases were reused war time dated cases for tests done in around 1960. They were used for fuze testing.
The 20 x 234/B is a necked down 30 x 184/B designed in Germany in the second world war. I am not aware of any genuine cases. A very limited series of these were manufactured from original Rheinmetall factory drawings and sold to collectors. They are clearly marked on the base with an “R” in a circle.
The 20 x 197/SR is a necked down USN 28 x 198/SR anti aircraft round. The “weapon” was a test barrel and was used to test projectiles at very high velocity in the 1950's..
The 20 x 181/R is NOT necked down. I’ve included it to give an idea of scale. The reason for the large cartridge case is because this ones a recoilless round with a blow out base. The weapon was adopted in 1942 by the Swedish arms as the “Pansarvarnsgevar M42”. It was a recoilless anti tank rifle with a weight of 12kg. Armour piercing capacity was apparently 35-40mm at 200m.
The 25 x 144 is a necked down 30 x 173 GAU 8. With the demise of the GAU 7 there was still interest in a gun which could fire 3000 grain 25mm shells at a muzzle velocity of 4000 fps so some 30mm GAU 8 cases were necked down and fitted with 25mm GAU 7 projectiles. Two different case lengths were manufactured, one with a 6 inch case, the other with a 5.75 inch case. The development ceased when no one was interested in investing money in the project.
The one on the right is the 20 x 135 which appears to be a necked down 25 x 136 KBA. I don’t have any more information on this so if anyone has any info I would be interested in knowing more about it.
All rounds shown are INERT and legal to own.
Dave.
The photograph shows a selection of rounds which with one exception started life as larger calibre and were necked down for various reasons.
From left to right:
The Bofors 20 x 311/SR is a necked down Bofors 40 x 411/SR anti aircraft round. The cases were reused war time dated cases for tests done in around 1960. They were used for fuze testing.
The 20 x 234/B is a necked down 30 x 184/B designed in Germany in the second world war. I am not aware of any genuine cases. A very limited series of these were manufactured from original Rheinmetall factory drawings and sold to collectors. They are clearly marked on the base with an “R” in a circle.
The 20 x 197/SR is a necked down USN 28 x 198/SR anti aircraft round. The “weapon” was a test barrel and was used to test projectiles at very high velocity in the 1950's..
The 20 x 181/R is NOT necked down. I’ve included it to give an idea of scale. The reason for the large cartridge case is because this ones a recoilless round with a blow out base. The weapon was adopted in 1942 by the Swedish arms as the “Pansarvarnsgevar M42”. It was a recoilless anti tank rifle with a weight of 12kg. Armour piercing capacity was apparently 35-40mm at 200m.
The 25 x 144 is a necked down 30 x 173 GAU 8. With the demise of the GAU 7 there was still interest in a gun which could fire 3000 grain 25mm shells at a muzzle velocity of 4000 fps so some 30mm GAU 8 cases were necked down and fitted with 25mm GAU 7 projectiles. Two different case lengths were manufactured, one with a 6 inch case, the other with a 5.75 inch case. The development ceased when no one was interested in investing money in the project.
The one on the right is the 20 x 135 which appears to be a necked down 25 x 136 KBA. I don’t have any more information on this so if anyone has any info I would be interested in knowing more about it.
All rounds shown are INERT and legal to own.
Dave.
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