I tried a few things this evening, and I think I found the problem -- the shoulders are expanded on the problem cartridges. Here's a picture of one, and where the arrow points you can see a slight swelling. This one is from a previous batch of Federal cases, and the bolt would not even close on this one. I measured the outside diameter of the shoulder on this one, and it was 0.4400 inches. Another cartridge that the bolt would close on was 0.4345 inches. I also chambered many fired cases, and all of them chambered just fine. In addition, I measured the neck diameter of the functional and non-functional cartridges, and the necks were a consistent diameter. So now it seems the problem is the shoulder diameter, and the problem appears to come from my reloading process. I hope to reload more cartridges in the coming week, and I'll try to identify what step in the process is creating the problem. Again, I appreciate everyone's help.


[Linked Image from i.ibb.co]