Quote Originally Posted by Frederick303 View Post
Also you can date the barrel if you can locate the BSA proof date mark. That would be small crossed swords with a letter above the handles of the swords if pre WWII. The dates stated at A which correlates to July 1921 to June 1922, C correlates to 1923/24, etc. I think I or J might have been left out.

Post war the crossed swords will have a letter combination on either side of the crossed swords like (BB -1951), BC -1952, etc. London will have no such date mark though.
Just quick clarification, they are Birmingham Proof House markings, rather than BSA's (By law, only the Birmingham Proof House and the Gunmakers Company are allowed to Proof Firearms) and they are supposed to be sceptres not swords. (I know that they don't look much like swords but then the Gunmakers Seax takes a bit a leap of belief as well.)