I have a custom 338 Lapua Magnum that I have put just over a hundred rounds down range. I bought 100 rounds of Lapua brass and selected 50 to do initial load development. I found a the load of 92gr H1000, Fed 215M primer, 300 gr Berger .015" off the lands to hold less than 1/2 MOA with no pressure signs. This load worked well until I bought a new lot of powder and started to notice a stiff bolt lift after firing. I figured this had something to do with newer lots of powder burning hotter. The bolt lift wasn't too bad, but still was stiff so I bought an 8lb jug and decided to redevelop a load. I have no chrono results, but am getting a new one soon. I started at 88 grains and worked up to 90 grains, however, every round had the same stiff bolt lift. This didn't seem right to me so after I FL sized the brass with a Forester benchrest sizer, I decided to run one in the gun. After being sized it gives me the same stiff bolt lift as if it were fired. New brass has no issue. I bump the headspace back .002" when resizing. I even bumped the headspace back to what the new brass is, which was approx .004" and it still has a stiff bolt lift. The only time I had a stiff bolt was with once fired,resized brass. The last 10 rounds were on their third firing and these have had the stiffest bolt lift yet, with a reduced load of 90 grains. Inspecting the brass further, about a half inch above the extraction grove it measures .005" wider than factory new brass. I marked a case with a sharpie. When I chambered it, it showed a rub mark at this same area. Obviously it is contacting there. My question, is my sizing die not sizing the cases enough? The only real resitance I feel is the mandrel going through the neck. The other possibilty I've been told is that I might have an oversized chamber. Has anyone had anything like this happen to them? I would appreciate any ideas. Thanks.