So my friend brought over his 7mm remington magnum along with 40 pieces of brass. All the brass was from brand new hornady factory ammo. After tumbling and resizing the brass with a lee full length die he tried to chamber a round and it would not chamber. So we decided to try the rest of the brass and almost half of them would not chamber. We checked trim length of the ones that would chamber and they are at 2.490. A few of the ones that would not chamber were the same or slightly longer at 2.500. I trimmed them all to 2.490 so they match but all the same ones would not chamber. I know the die is set right. Even tried going to 1/2 turn more. Still nothing. I can't for the life of me figure out why they won't chamber. I have had this problem with 308 and 223 military brass in a bolt action before but never a standard caliber that has been fire formed to a chamber. Any ideas?