.5 BSA Observers Gun

[clarkbr]

Hello All,
I am trying to figure out what the .5 BSA Observers Gun cartridge was.
I understand it was the Model 1924 BSA machinegun, but what cartridge did it use?
I found a little snippet of information that said it was similar to the .50 Vickers, but different (whatever that means).
Can anyone educate me on the cartridge and does anyone have a photo or drawing?

Thanks a bunch!

Brian

 

[TonyE]

The BSA .5 inch Observers gun was essentially an overgrown Lewis and was one of several .5 inch weapons being considered by the Royal Air Force in the 1920s. Work had stated in 1918 of the .600/.500 cartridge which had gone through a couple of versions, first rimmed, then belted, and emerged about 1922 as the .5 Vickers.

The first version of the BSA gun was tested in 1924 and used a cartridge very similar to the Vickers but with a different shoulder length, head diameter and a bullet of different ogive. This ammunition was made by Kynoch and a drawing is attached. Once the .5 Vickers had been accepted by the military BSA changed the calibre and the later version of the gun tested in 1928 was chambered for the Vickers cartridge.

As a matter of interest, BSA also developed in 1924 a smaller version of the machine gun chambered in a unique .300 inch cartridge. The Kynoch drawing of this round is intriguingly titled "BSA .300 inch Cartridge (Greek)" suggesting interest from that part of the world.

Regards
TonyE

 

[clarkbr]

Thanks TonyE,
Your information is as illuminating and interesting as ever.
Now you piqued my curiosity regarding the BSA .300 inch Cartridge(Greek).
I'm totally unfamiliar with the experimental or development cartridges of the UK.
Can you recommend a good source of reading material?

All the best from the Puget Sound Region.
Brian

 

[Tony Williams]

The BSA .5 inch Observers gun was essentially an overgrown Lewis

In purpose, yes, but I've always understood that it used a long-recoil rather than gas-operated action.