Boyes Anti Tank Rounds

[Carillonmuseum]

What and why is the raised rim just above the extractor rim on Boyes anti-tank round, I do not think I have seen it on any other type of ammunition? One theory amongst our volunteers is that it is to prevent it being loaded into another weapon, but I have my doubts. You help would be appreciated.

 

[beihan62]

Hi,another round with this belt is the 20X138B Solothern Anti aircraft round,
Don,

 

[glevum]

The original reason for the raised rim or belt was to ensure correct headspacing on rimless rounds.

It is not uncommon

 

[smle2009]

....and the 30mm Aden.....also its Boys not Boyes

Tony

 

[gravelbelly]

The Boys case is very similar to .50 BMG but the bigger diameter neck results in a slight shoulder so it is possible that headspacing was a problem resulting in light strike misfires before the belt was added. Some magnum type cartridges are also belted for increased strength.

gravelbelly

 

[Tony Williams]

Rheinmetall Borsig were very keen on ammunition with belted cases for use in automatic weapons in the 1930s and 40s, as shown by the cartridges they produced for Luftwaffe Flak guns (photo from my Ammo Photo Gallery):


20x138B (2cm Flak 30/38), 30x184B (3cm Flak 103/38), 37x263B (3,7cm Flak 18/36/37/43), 50x346B (5cm Flak 41), 55x450B (5,5cm Gerat 58, replica)

Other well-known cannon cartridges with belted cases are the Russian 23 x 152B and the Mauser 27 x 145B, as used in the BK 27 aircraft gun fitted to the Tornado, Typhoon and Gripen warplanes.

 

[AE501]

In the hunting rifle field the belted base is used on what are known as 'Magnum' cartridges such as the Holland and Holland and Weatherby Magnum cartridges. The Winchester .22 Magnum cartridge is rimfire so does not have such a base.