Do you concur ?

P1180763 by SGMTB, on Flickr

P1180761 by SGMTB, on Flickr

Looks like a .303, but I don’t have one around for comparison. I’ve got a .45 Mag kicking around somewhere, but that doesn’t really help much, does it? 😉

It’s a rifle cartridge, and rimmed (heh), like a .303.

Try here

I’m getting 57mm from mouth of case to bottom of base for mine, yours looks longer, might might be because you took the photo so close.

Mk. 7 ball made by Greenwood and Batley, Leeds, UK in 1948.

From here

Just measured it with the micrometer and the length is 56mm

and 7.93 opening diameter.

So a 303.

Thanks chaps.

Yes, definitely

Greenwood and Batley ammo Factory
1948
Mark VII 174 grain ball bullet