I have a 1937 Brazillion that is in great shape but won't group at all. I miked the chambers and all were a consistent .455/.456. I miked the barrel at the muzzle and the grooves came in at the same .455/.456 and best I could get at the lands was about .450 to .452. I'm considering trying some .455 Webley bullets , but custom moulds are available in .454. I have 100 pcs of .45 auto rim to try them in. Sooooo. Anyone have any experience with this? If the chambers are roughly .4555, is the .455 to tight?