My Colt (another AWB rifle), has a 1 in 9 20" and really likes 68gr Hornady bthp around 2800-2850 with Varget. I've had that rifle since 1999 when I was 20 and cannot bring myself to make modifications. This one's fancy groups will be hampered by the scope. Eventually this barrel and handguard will be replaced. I want to put a 18" 6mm ARC that I spin myself on this receiver set.
Funny thing about this build is I bought the barrel and free float kit around 2003. The receiver set in 2008 and the trigger about 5 years ago. I've built 4 others over the years but never could figure out what I wanted to do with these receivers. Why I say it didn't cost me much, hahahahahaha.