Ken;
If the barrels are in sound condition you will have no problems shooting 2.75" shells through it. If you don't handload, shoot the lowest pressure, payload you can find. 1oz. to me is a heavy load anymore as I shoot 3/4oz. loads in my 12's, 20's and 16's. Easier on that cracked stock and your shoulder. There is some readily available 7/8oz. factory stuff out there that's real mild too. Enjoy and don't make this your last Parker. (I bet it won't be).
