6MM BR TeJas
I witnessed this fast twist wonder it really shoots, Even on crows it works great. I have a similar gun with a 12" twist, chamber cut with the same reamer. the loads with 36gr AA2230 55gr Sierra Blitzking shoot 3917 fps,ES was 10 and the SD was 4 group was good for four shots but shaky old me blew it out to .400"Dam! 6mm br imp/40* fANTASTIC!