I have a Magna Classic .44 mag with .427 throats and a 24-3 Lou Horton .44 special that will chamber .44 mag. To address the OP's question, in my mind, there is no excuse. Whether it's a .45acp or long colt (the usual offenders) there's just no reason for throat variations to that extreme or to the extent that they do not properly match the bore. To say that it's within SAMMI specs may be correct, but to me, it's an excuse for an inferior product. Would it really cost any more to cut a proper sized throat? The reputation for a superior shooting revolver is already there. Smith, Colt, Ruger and even Uberti have such reputations. They're finely made machines, yet, at times, they all fail at this simply corrected (and basic) production failure.