Redding dies are the best, that said. Assuming the brass is clean. A few questions; Are the dies new and did they come to you in an unopened box? Possibly the dies are not "300 PRC"; check the box label and see if it matches the engraving on the body of the FL die. Some monkeys messing around the store might have opened the box and inadvertently put the wrong dies onto the wrong box. Had that experience one time, the green box had been opened, lucky I checked them before I checked out. Did you clean the insides of the FL die, they often come with a good coating of rust preventative inside the die, and at 30 degrees temp, I would think that preservative could be really thick! The cold could be affecting your case lube? Check the decapping pin/rod and neck expander. Bent rod? wrong size neck expander on the rod? Whatever you do, don't force that case up inside that die with excessive force, you may never get it back out. It's possible the die is just miss-labeled, miss boxed? You may have to move indoors.