Nice English hammer gun. Out of proof?

[Daryl Hallquist]

Maybe we should say that prior to 1925 the 12 over C in a diamond meant chamber length of 3" or longer.

[Drew Hause]

This is a 16g with pre-1925 proof with 2 1/2" chambers



Engelhardt in the 1962 Gun Digest "European Proof Marks, Proof in Great Britain" stated that the 12 over C was not used prior to 1925, which is obviously incorrect, and didn't mention 12 over LC.

I think we can say that gauge over C means "standard chamber length" - 2 1/2" to 3" (after 1925 anyway) and 'LC' means 'long chamber"