Am looking at a 12ga. double made in England in excellent original condition. My question the gun is 2 3/4in.chamber, 3 1/4tons proof.
This equals 9,682 P.S.I. I think most all our shells are higher P.S.I. than this proof, so it would not be safe to shoot them in this gun.
It has steel barrels. What do you guys think ?

Dirty Harry

P.S. I don't shoot RST or Gamebore.