Punkwood2k, I highly recommend you slug your barrel before ordering bullets. My PT145 barrel is very oversized and produced erratic shot groups and leading issues with my reference 200 gr SWC with 5.0 gr of W231/HP-38.
When I realized the groove diameter of the barrel was like .455" instead of .451", I considered ordering larger diameter bullets but decided even larger sized bullet won't provide adequate bullet-to-barrel fit.
I was shooting 18 BHN Missouri Bullet (
IDP #1) and ordered softer 12 BHN bullet (
Bullseye #1). Guess what? Accuracy returned and leading went away. The softer bullet base was deforming (obturating) to provide better bullet-to-barrel fit.
To test, I even loaded lighter plinking loads of 200 gr SWC and 4.0 gr Promo/Red Dot and this load also produced accurate shot groups.