I have a 20" .875 dia. Bartlein 6.5 Grendel barrel that appears to be undergassed according to most everything I've read and what I've experienced in about 200 rounds of testing. Gas port is .081-.082. I have number 42 and 44 straight fluted chucking cobalt chucking reamers (086 and 0935) and am about to step into bumping up port size in stages. Is there a recommend drill speed to run these at or anything I should know prior to jumping in? Barrel appears very accurate and don't want to screw the pooch here. Thx for any shared wisdom.
