A couple things, back the crimp off to .471" and try again. Crimping tighter is magnifying the problem, as you go tighter and tighter the problem will get worse. If you still have the problem read on, if not continue life happily.
Plated bullets? If so get some jacketed bullets or lead bullets to try, Fix it? If not read on.
Lead bullets? If they are at least .451" in OD read on.
Your sizing die isn't doing its job, plain and simple. Your sizing die is not sizing the case down enough to provide adequate tension on the bullet.
In this case I would recommend you buy a cheap Lee 3 die carbide die set for about $20.
Set your crimp at .472" at the case mouth. Yes, I am telling you to load with basically no crimp. It will work. Trust me.
When you get into hard kicking loads you might need to switch to a roll crimping die, but the loads you are using are very light and a taper crimp should handle them and a lot more without issue.