I LOVED a semi wad cutter 9mm, IRC 127gr bullet. Gun shot it really well, until it didn't. Had a bullet keyhole at 21', and when I cleaned the barrel, pulled out strings of lead. Why? Wasn't overly hot, bullet was sized to my barrel, according the company that cast the bullets. I'd have to pull the data out of my book, but IRC, it was only running at 1,000 fps.