For the contour cited,the Hunter wearing DBM is a nice way to fly,without any bullschit.
Barrel was chopped to 21" and it's superb in Kreedmire. I'd not want a 6BR any longer than that. Top of frame. #4 Hart in a Classic wearing DBM below it,at 24" in 260AI 1-8".
COAL won't be an issue,but reliable Feed/Function will,if you don't go DBM and Primal an AICS mag. Hint.
Mike's approach ain't horrid,but I'd rather shim the nose,so as to retain good ride height of loaded rounds in relation to the bolt's nose. My 20" 8" Bart' 6BR Montucky,is fed in sucha manner and is flawless with the nose shimmed...but had issues with the stern shimmed instead.
Very easy to essentially create a funnel,to guide things into battery,even ala CRF. 700's are more forgiving.
18" 1-8" Hawk Seven based 6BR fed ala DBM with AICS poly 10's.
A 21" #3 1-8" or faster 6BR in a Classic wearing DBM and 5rd Primal guts,would make for an exceptional parcel................