[pug]

Spook this is one of those threads that may take on a life of its own. I have had bullets come unseated in a couple of different calibers however none in the 300/221. As you stated because of the depth of the shanks seated it is unlikely that one would unseat with one chambering. However they can move when chambered in in auto and how much can only be determined by measuring it. I have measured .025" to .050". You may run enough neck tension that they don't move.

too many hobbies the Lee factory crimper is a collet crimper and will form its own cannelure when squeezing the bullet. The Redding dies have a roll crimper that rolls the lip over into the cannelure. Before worrying load a dummy round and drop the bolt on it. If it moves too much then crimp it if not don't bother. Accuracy wise I prefer not to crimp. Factory ammunition is crimped because it gives a more uniform start pressure which improves accuracy even though there may be some slight load variations. Your handloads are suppose to be perfect. :)