Could it be the cases being a bit too long, causing the crimp to be applied a bit early, prior to fully seating the bullet? The opposite could also be true....case being too short and not getting enough expansion on the mouth causing the bullet to hang up when seating. These issues might be more difficult to notice in a progressive press, vice a single stage. Suffice it to say you can't mix LeverRevolution cases with standard cases because the LR cases are shorter in, I believe, all calibers. Are you crimping into a grove? Been awhile since I've loaded anything straight walled. I know I've always been very cautious to ensure the case was fully inserted into the shell holder and the bullet started as straight as possible before heading up into the die. I also tend to partially seat, then rotate the case 180 degrees, then seat the rest. Or partially seat, then back it out to look at it, then seat all the way and crimp. Short, fat bullets don't provide as much opportunity for centering in the case during the seating process. I would also double check to see if the die is still secure in the press and the seating stem secured in the die.
