Frank... definitely keep an eye on the carbon ring if you decide on Rl15... I just got bit in the ass last week in my 6BR because of that... Went from shooting 1" at 300yds to shooting about 4."
I clean after every session and match.. I don't know how it got there, but it came out of nowhere!
I clean after every session and match.. I don't know how it got there, but it came out of nowhere!