Jim in old guns that were over bored to shoot brass shells with over size wads do you think plastic wads designed for a smaller bore diameter can cause pressure problems and or velocity loss.
I traded for the nice old Parker, at the Beinfeld show, thinking it would be good for BP skeet matches. I was told it was IC and IC, nothing about an odd bore size. When I got it home and measured it, I found this overbore size and Full/Full chokes. I bought a case of brass shells and got all rigged up to load them. The smokeless. plastic wad loads I used shot fine but I never chronographed them. To me, it seems likely the pressure and velocity would be somewhat less but that's just a speculation on my part. Anyway, I disliked the ordeal of dealing with the brass shells and sold gun, shells and all the reloading stuff for them.