Fit is King! Bullet diameter has been well covered but other dimensions affect accuracy too. Fit is important to Firearms and Bullet Mold Manufacturers too but not always in a good way. Ammo MUST FIT THE GUN! Forward drive bands on bullets get reduced (Elmer's Complaint) and cylinder throats get moved forward so the two can't interfere with each other. If you are looking for accuracy you might want the forward drive band Inside The Throat so there was No Jump to the throat or chance of misalignment. Lots of us have been happy with the H&G #503 with a little over .010" of Full Diameter Drive Band ahead of the case. There is now a Hollow Point that goes deeper with approx. .140" of Full Size Drive Band ahead of the case. The MP-Molds-Larsen-C432-250-RF. http://castboolits.gunloads.com/show...4-Hollow-Point Here are pictures of unsized dummy rounds (4325") chambered in an Anaconda, Redhawk and S&W 629 with throat marks at .08", .12" and .14" from the end of the (Starline) brass respectively. Throats are .4313", .432", .4313". I have several hundred loaded and will put them up against the #503s and 432-640s next trip to the range. Could be a winner.