| Cat. No. | Introduction | Obsolescent | Obsolete | Remarks |
| L. of C. A.7772 57/Tanks/1313 10th August 1933 |
L. of C. C.2022 57/SA/1385 24th August 1944 |
Carden Loyd M.G. Carriers |
This was the prototype of the .5″ Vickers M.G. and only a handful were made. They were mainly for experimental purposes and used in the prototype tankettes and Light Tanks of the period during the 1930s when Vickers-Armstrongs were trying to produce a cheaply-made but efficient Infantry support vehicle.
This first gun was just a scaled up version of the .303″ Vickers Mk. I with very few differences in mechanics other than the sizes. There was no need for a muzzle booster in any of the .5″ Vickers guns due to the superior power that the .5″ cartridge held.
All the .5″ calibre Vickers guns had the fluted waterjacket as the weight considerations that were required to make the .5″ gun a feasible project were that all components that could be lightened should be and the fact that fluting took longer was not a problem as most of the production was pre-war and thus having no immediate requirement in substantial quantities. The weight considerations were an important factor as the Mk. I gun which was the lightest of the .5″ series was 50 lbs without water and with water it was near enough 60 – 62 lbs. Quite a lot by any means. This version of the gun also had the slowest rate of fire which was a mere 450 rounds per minute.
