It depends on the weight of the bullet, etc. Technically, a full wadcutter, if one existed for the .277 caliber, would load flush or a bit past the case mouth. Jump to the rifling would be atrocious and accuracy probably terrible. So I guess minimum length would be the length of the case without a bullet seated. I have seen 90 grain bullets seated backwards into the case—sort of like a wadcutter—and the end was only 1/8” past the case mouth. I ain’t sayin’ I would approve of this and I didn’t see the round fired, but I understand they will shoot and are quite devastating at close range. Maximum cartridge length is probably much more important than minimum length. I think all books give the maximum lengths. Good-luck…BCB