Burrard talked about muzzle flip. Basically his consensus was the gun could be stocked to accomadate the flp for whatever length bll was desired. It would however be a mistake to have a 2nd set of bbls fitted of a different length as the fit could not accomadate both lengths. Been awhile since I read on this but as I recall he said the longer bbl would have greater down flip, don't recall any having up flip.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra