Thanks John. Most of my usable cases are reformed .303s.

However the rifle presented here came from a deceased estate with a couple hundred mil-surp rounds with nickel FMJ projectiles and small-diameter domed Berdan primers. Headstamp is "AI" which I understand indicates Dutch manufacture by Artillerie Inrichtingen.
The cartridges were all in clips with 10 clips per box IIRC.
Most of the clips surplus to my requirements have already been given away!
Headstamped date is 23C, not sure if that means 1923 but they either dud-fire or hang-fire badly so could be!

The rim diameter of the AI brass is 0.526 inch.

...and I take your point about bevelling the rims after turning them down Matt. Always do this anyway.

But I am amazed at your sterling efforts to improve operation of the clips! A quick spray of aerosol silicone is the most I have entertained!