What press are you using? Is it camming over a tad? are you lubing the cases? Have you trimmed to length before resizing? As 1bama said, its prolly that the shoulders are not being bumped back enough. Try screwing your die down a little. In custom actions, neck thickness would cause a tight fit but your problem is prolly either cases to long, (need trimming) or your shoulders need to pushed back more. Stoney point (now hornady makes a gauge that you can put on your calipers to measure shoulder bump and you can just measure the length with your calipers. good luck
