If it was a mixed lot of brass the amount of spring back will vary and the cases will be different sizes. Next loading you may consider annealing the cases. If the above suggestions are not successful then I might be tempted to go all the way and even de-cap the primers and start at square one with annealing, case trimming and champfering, FL bump size and maybe collet size as well. Then double check the seater die especially if it has a crimp feature like RCBS. Make sure you have clearance of the crimper and check over all length to make sure you are not into the lands.
Might not hurt to clean the chamber and barrel, I have had a carbon ring cause bullet jam when a clean barrel had clearance.
