1 key hole in 600 isn't quite enough to have me scrap the whole project. I want to do some more testing before I call it bad. I'm thinking I need to setup a big sheet of cardboard at 5 yards and blast the heck out of it. Do a couple 100 round dumps and check for key holes. See if I can force the thing to key hole. Hell, for all I know the one key hole I saw was from somebody else shooting my target. I thought maybe it came from my 5.56 but it was too long. Honestly it looked too long for the 5.45. I need to pull one of the rounds and see what the OAL of the bullet is.Well I've seen 5.45's suppressed, maybe try a different type of 5.45?