The first I saw keyhole was M855 in an old Mini 14. (I know, how could I tell)
The other was a 17 Remington with 25 gr bullets and a slow twist, 20's shot great. So ya, voodoo all the way.
Then I've seen bullets that a barrel just didn't like for no apparent reason.
I don't know about top of the line, I've just seen better results with quality parts and guns. I've also seen and fixed enough cheap junk that I hate the thought of it. Threads that start out with what's the best AR for under $600 worry me. Maybe they will function just fine but more times than not, they don't, if they are shot enough.
Then again I spent $85 for a hammer the other day so maybe I'm nuts...
