Looks to me like they do not have a centerfire caliber or barrel length requirement. Only that the bullet must be of an expansion type bullet. Like soft led tip, Jacketed expansion round, hollow point and etc. I have a friend that is a law enforcement officer for the Mississippi State Police. I have sent him and another guy I know at Mississippi Dept. of Wildlife an e-mail. If you do not find out prior I will get you the confirmed answer.