I built a hydraulic press to do stuff like that. I've run .452 230 gr. FMJs through a .429 Lee sizing die and loaded them in .44 mags. I tried .454 255 gr. RNFPs in it and got acceptable results. 'Coarse, when you're just banging with a 4" wheelgun, accuracy ain't a big issue. Try this: run a .458 300 gr. JSP .45-70 rifle bullet through a .452 sizing die and load it in a .45 Colt case. Just looking at it will intimidate you.