First, let me say that I'm a novice at reloading. I've got a custom 7RUM that's only had about 50 rounds through it while breaking the barrel in. When I picked it up from my smith, he told me that he was having issues with some of the factory remington rounds chambering but thought that it was due to the varying neck size on the factory loads. He stated that the rifle has a match grade chamber and that some of the necks on the factory brass were out of tolerance. While breaking in the barrel with factory remington ammo I found that about half of it would chamber fine, and the other half would not. It wasn't a big deal to me as I gave the ammo that wouldn't chamber to my uncle who has a factory 7RUM and it chambered just fine for him. Now, I bought some bulk 7RUM unfired brass and am running into problems. I FL sized the brass with a forester die, checked overall length and neck dimensions and everything looked fine. However, once I seat the bullets they will not chamber in the rifle. The bolts ends up roughly 1/4 shy of being all the way. I've got some reloads from the breakin brass that chamber fine, and when I check the dimensions between the two (the once fired vs. the virgin brass) I cannot tell the difference. I was hoping someone on here could possibly tell me what I'm missing. I've got a neck turner so it wouldn't be a big deal to turn some of the brass, but as I stated above when I compare a round that chambers to a round that will not, I don't notice any discrepancies. Thanks.