What signs of pressure did those XTP rounds show? Flattened primers are a poor indication of pressures. You won't know what your barrel measures unless you slug it, no matter what you speculate by fired cartridge appearance. I have been reloading lead in my .44 Mag. Puma for 9 years and found two things; the gun will lead with any lead bullet less than .432" in diameter and my Puma won't feed SWC unless in Special cases. Many Rossi Pumas were manufactured with oversize bores (groove diameter up to .433") so the only way to know for sure is to slug the barrel...