.303 British Proof-Round

I recently got a .303 British cartridge, which I identified by the yellow primer seal as a proof-round. The headstamp says: “K” 10 o-clock; “67” 2 o-clock “7” 6 o-clock.
I read the headstamp as followed: Kynoch, Manufacturing date of the case 1967, Mark 7.
I searched my sources and I couldn´t find information about a Mk7 proof-round. Or is the only indentification-sign the yellow colour of the primer-seal.
Does somebody has a bit more information about this cartridge?
303011 303010

I could be wrong, but I believe that the yellow seal identifies a Ballistic Standard round, rather than a proof round, on British .303s.

John Moss

1 Like

I would suggest that John is correct and that your round is a ballistic standard rather than a proof load. British proof rounds in this calibre are very clearly marked with the prefix ‘Q’ and they also usually have a copper stained brass case. The ballistic standard round made by Kynoch in my photo has a very obvious yellow paint annulus however faint yellow lacquer rather like yours was also often used.



I am envious of those beautiful photos!

John M.

Thank you John!