Barrel wall thickness

[Craig Budgeon]

Drew my understanding of Britsh proof is that a 12 ga. exceeding nominal size (.729) by more than 010" has to be reproofed before the gun can be sold in England and is marked 12/1 on the barrel flats after successful reproof. Based on that understanding Gibbs would sell a gun with a bore of .735 and is still in proof by .004. Ed Good there would be many Parkers left in dealers gun racks if .030 minimum was the accepted number.

[Drew Hause]

That is correct Craig pre-1954.
1954-1989 the bore would be marked in inches, but I have seen some also marked with the 12/1.