I know the "big boys" aren't that popular at GSSF for several reasons including recoil, cost of ammo, etc. But I was running my 21sf today with some reloads (just started reloading) to see how it ran. And with my light reloads, I must say it felt like a 9mm with factory loads. I set up a little 5 to glock and my times were from 0 to .50 seconds slower than a typical 9mm run for me. I when pasting the targets I noticed out of 100 rds I had 3-4 that would have been scored better because of the larger diameter hole breaking the next ring - this would not have been so with the 9mm. I may give it a try in Anniston next month in Mas stock and Mas comp. BTW I'm loading 4.0 clays, wolf primers and BBI 200 SWC with mixed brass.