just thoughts i'ed tell you about my dissy's...
midlength....CMMG--- 1/7 CHROME LINED
carbean ... BUSHMASTER -M4lightweight- 1/9 CHROME LINED
and rifle gas...DELTON---NON-CHROME LINED- 1/9 twist not a HBAR , but pretty thick.
all have rock/river two stage triggers, two stag lowers, one no-dak-spud lower.
the lightest is the bushy, shoots pretty good.
the middy with the 1/7 is great with heavy bullets.
my favorite is the delton, with the rifle gas... slightly nose heavy, but very steady.
and soft shooting.
and the most accurate of the bunch.
altho' the middy and bushy are very good too.