I was shooting my .44mag rifle today and one of the rounds I loaded for the thing would not chamber and I noticed the bullet had seated below where it was crimped.

I was shooting a batch of 240g wad cutters and I believe the problem was a weak crimp on that round. It was in the middle of the magazine(tubular) and all the other rounds shot fine.

Do you think it was a weak crimp? What else would cause this?