What they said. David Trevallion once told me that if the gun is within proof limits and the right shells were available, that gun was fine no matter when made. We were speaking of percussion conversions to center fire.
That's a very good point Montana. DT would know for sure, probably having seen more pinfire to centerfire conversions in British guns than 10 American gunsmiths.
Just as an example, I just picked up a very early J. Blanch and Son damascus barreled hammer gun that I am almost certain is a pinfire conversion. The gun has a typically older back lock action, and underlever with gorgeous barrels and beautiful engraving and wood. I have shot low pressure 2 1/2 inch 12 ga reloads through it and it performs beautifully. The barrels checked out pretty well, not too thin, in fact thicker than I have seen on many an English sxs being 30" and as light as the gun is.
I may attach a few pics of it on another thread and you can see why I think it is a converted pinfire, with the pinhole cutouts in the tops of the barrels at the breech, the small non-rebounding hammers with definite aftermarket stock cuts for the nipples of the centerfire pins and the very very low SN of the gun, which dates it in the 1870's.
Anyway, not to get too far off the subject, but all of that is to agree with you and DT/CC that if the condition of the gun is such that it is still in proof and you have the right shells, the gun is fine no matter how old. Smallbore's late season pheasant gun sounds fascinating.
Brad