20 ga chambers

[fly by night]

Hi all,
Just bought a 20 ga Pa Sterlingworth which is in great condition, with the orig barrels. I understand most of these left the factory with 2 3/8" chambers, but I inserted a 20 ga chamber gauge (.685") and it went in to 2 3/4". Does that mean it has been modified? Should I still shoot 2 1/2" shells in it? If so do folks recommend RST or polywad? Thanks,
FBN

[Researcher]

I have two Fox 20-gauge doubles (1913 and 1922) that have had their chambers lengthened to 2 3/4 inches, but they are both right at 6 pound guns, and I don't much worry about it. I once had a little 5 pound 6 ounce CE-Grade with the original short chambers. I wouldn't recommend anything beyond the little 3/4 ounce 2 1/2 inch Lyalvales for it. For high volume shooting at clay targets I use 3/4 ounce reloads in STS or Gun Club hulls in my old 20-gauge doubles with 2 3/4 inch chambers, just to be easy on me and them.

I've never used the Polywad shells, but the little RSTs are the next best thing to my beloved Lyalvales. I don't have any Lyalvale 20s left and only 2 1/2 boxes of their 7/8 ounce 16-gauges.

[fly by night]

Researcher,

Thank you for the information. Mine was made in 1924 and is a hair under 6 pounds. I will go with the 2 1/2" 7/8 oz. RSTs.

FBN