Unknown Cartridge

This cartridge by Royal Laboratory is primed, but empty. What’s the purpose of it?
Looks similar to a 500/450 No.1 Musket, but measurements are closer to the 470 Experimental?
Does somebody recognize the head-stamp?
What caliber is it?

Welcome pablo

Looks like a .450 Machine Gun chamber blank. A MK II judging from the way the “C” (Cordite) is canceled & an extra “I” added. However I may be wrong about that as my MK II blank is marked just “R /|\ L II”.

Mine weighs 335 grains total & is loaded.


Thanks for the info!
According to “Cartridges for Collectors” by Fred A. Datig, Volume II, the “R /|\ L CI” head-stamp was used on the .470 Experimental.
Do you think surplus .470 Experimental mk I cases were used to manufacture .450 mk II Machine gun blanks?

Hi Pablo and Pete.

This is a 45 Machine Gun Mk I Cordite case which was either rejected and reloaded as a Mark I blank (thus the cancelled headstamp), or a fired case reloaded as a MK I blank (again, cancelled headstamp). There is a similar blank made from a MK IV ball round with a similar cancelled headstamp. Just the Brits being frugal (cheap) and reusing the cases.

Neat headstamp.



Fred had it wrong, the co-called .470 Experimental was a cartridge that when accepted, the official & correct name was: Cartridge Machine Gun Ball .45 inch Cordite Mark I. So not a .470, Fred did the best job he could with the knowledge that was available to him & his books are very useful.

You will find other mistakes in Fred’s and other books, best thing to do is to keep buying books & using them. New information is being discovered every day, by folks on this forum putting odd bits together & having an “eureka” moment.

If this subject interests you I would like to recommend the book BRITISH SMALL ARMS AND AMMUNITION 1864-1936 by Peter Labbett, Also I think Tony Edwards site: https://sites.google.com/site/britmilammo/home would be of major use to you.

The .45 M.G. is the correct name and not .450 MG (as I wrongly wrote above) as the .450 versions were MG cases based on the .577/.450 Martini Henry case.

powdertin has it right.

Thank you all for the info!

Pete, that makes sense!

I’ll read “BRITISH SMALL ARMS AND AMMUNITION 1864-1936” tonight!!