Marks often found on Enfield Riflesicon that have been exported for sale from the UK.

"BNP" ".303" "2.22" on barrel and under that is either "18.5 or 18+ or 184 TONS" .... means that the rifle was tested for safety by Birmingham Proof House showing caliber and chamber length. As required by British law, any firearm offered for commercial sale (regardless of military proofing) has to undergo a pressure test. Passed firearms were stamped, usually on the barrel and receiver.

"NP" was the Birmingham Nitro Proof between 1912 and 1954 and "BNP" is the Birmingham Nitro Proof after 1954

"Englandicon" is sometimes seen on Enfield rifles and it's the British private export mark pre-1968

Hope this helps somewhat...

Regards.
Badger