To start, yes I did some reading and no, I wasn't able to find any solid data about this. Quick data, I own a S&W 460 and wanted to make some light loads with some Berry's 250g coated projectiles I have. Not being about to find 45 Colt die sets online, I went to my local Bass Pro and they had sets from Lee and Hornady in stock. The Lee was their 3 die set and looking it up, definitely did not have a crimp die in the set. The hornady was less obvious and the online data was confusing, so I just went ahead and bought it...Hornady makes high quality dies so I figured I couldn't go wrong. I got home, dug into the dies and figured out the Hornady set doesn't have a crimp either. This confused me, so I emailed Hornady and that said the seating die is a seat/crimp die. Long story short, it is not. The die had a single adjustment, not 2 like all their other seat/crimp dies do. I decided to make some loads with the Berry's over 5.8g of Trail Boss and 9g of Unique. They both shot well from the 460. I didn't test accuracy past 10 yds and I didn't chrono them, I mostly wanted to function test. Running a few and pulling an unshot round from the cylinder, neither seemed to crimp-jump at all (yes, I know, no crimp was there). So...does this mean I'm good to go with no crimp? If not, what kind do you guys use? Taper? Roll? Something like a Lee Factory Crimp? I see Lee also makes a collett crimp but for the life of me I can't understand why that much crimp would be needed for a 45 collt. Any advice is welcome.