AA Hulls Stuck in Spolar Crimper

So I’ve had a couple of AA hulls get hung up in the crimping stage to a point that the base pulls off the hill. Now, the hull is stuck and I'm trying to pull it out. Not the best picture.

Any idea why this happens?

 

Sometimes at the final crimp a reloader will mushroom a shell. There are tools that can remove the mushroom effect and even some that will put a taper on the hull so it will shuck out of the chamber with less drag.