Opinions vary.
Scroll down about 1/2 way here for several, and links to previous discussions on DoubleGun
https://docs.google.com/document/d/1...A/edit?tab=t.0
ONE study of modern loads in a 12 gauge showed an average increase in pressure of 700 psi. Please note there are
NO studies regarding modern 16g and 20g loads, and that Parker chambers were typically slightly shorter than 2 9/16" for 16g and 2 1/2" for 20g. I had a 1924 20g Parker with chambers almost 2 3/8". It is likely the case mouth of 2 3/4" 7/8 oz. target loads entered the forcing cone as recoil was wicked, possibly explaining the previous repair of the cracked stock.
SO, if the question is regarding a 12g Parker, that has been evaluated by a qualified smith,
with measurements of wall thickness at the end of the chamber, the answer is yes, using loads with pressures for which the gun was designed.
I would not use 2 3/4" shells in a 12g 2 1/2" chambered lightweight British or Continental game gun, and would NOT use 2 3/4" shells in a small frame 20g with 2 1/2" chambers.
Some nominally 2 3/4" 20g and 16g hulls are shorter, but components used by ammo makers change so it would require measuring a collection of empties.
Winchester Super-X 16g 1 oz 1165 fps 2023
Threaded Mode