The attached photographs show a solid metal replica of the Rheinmetall-Borsig 55 x 318B round which was under development at the end of the war.
It is the round photographed in Tony Williams excellent book "Autocannon. A history of automatic cannon and their ammunition" that was published in 2022.
www.bookworldws.co.uk
I have shown it next to a 30mm Mauser 213 for scale.
The following information is taken directly from Tony's book, page 106.
"The round used a part-combustible case and was intended for a recoilless gun. the shape of the case looked conventional. but there was a steel base 96.5mm long, the rest being made from nitrided cardboard. The overall length of the round is 500 mm, the weight 3,000 g (of which the cartridge case weighs 1,000 g, the propellant 500 g. The rim and body diameters were both 67 mm.
This fired the same 1,480 g M-Geschoss shell at the same 600 m/s MV as the conventional MK 112 (55 x 175RB) but used far more propellant, the extra gas generated being diverted into a tube and expelled to the rear of the gun in order to balance the recoil (apart from a proportion tapped off to drive the belt feed). There are no known survivors of this round, not surprising given the case materials.
The MK 115 weighted 180 kg, was gas-operated and belt-fed. The gun was 330cm long, with a L/24 barrel. Despite the large case, the rate of fire was planned 300 rpm."
A photographs of the gun is shown on page 107 of Tony's book, ref also Chinn.
If anyone has any further information or even photographs of a genuine round I'd be interested in seeing them.
Thanks.
Dave.
It is the round photographed in Tony Williams excellent book "Autocannon. A history of automatic cannon and their ammunition" that was published in 2022.
Autocannon. A history of Automatic Cannon and Their Ammunition - Bookworld
Autocannon is a comprehensive history of the development of automatic cannon and their ammunition from the end of the nineteenth century up to the present day. The book includes data on about 200 different cartridges and 400 cannon, and has nearly 500 illustrations. It is the culmination of...
www.bookworldws.co.uk
I have shown it next to a 30mm Mauser 213 for scale.
The following information is taken directly from Tony's book, page 106.
"The round used a part-combustible case and was intended for a recoilless gun. the shape of the case looked conventional. but there was a steel base 96.5mm long, the rest being made from nitrided cardboard. The overall length of the round is 500 mm, the weight 3,000 g (of which the cartridge case weighs 1,000 g, the propellant 500 g. The rim and body diameters were both 67 mm.
This fired the same 1,480 g M-Geschoss shell at the same 600 m/s MV as the conventional MK 112 (55 x 175RB) but used far more propellant, the extra gas generated being diverted into a tube and expelled to the rear of the gun in order to balance the recoil (apart from a proportion tapped off to drive the belt feed). There are no known survivors of this round, not surprising given the case materials.
The MK 115 weighted 180 kg, was gas-operated and belt-fed. The gun was 330cm long, with a L/24 barrel. Despite the large case, the rate of fire was planned 300 rpm."
A photographs of the gun is shown on page 107 of Tony's book, ref also Chinn.
If anyone has any further information or even photographs of a genuine round I'd be interested in seeing them.
Thanks.
Dave.
