Any and all case trimmers with pilots that go inside the neck are garbage, sorry to inform you of that fact, sell it off and get one that doesn't have a pilot to score the inside of your necks with, may I suggest a Wilson, simple easy accurate is the reason every Benchrest shooter uses one.
You may be using too small of a bushing, making it too tight on your pilot. Mic both and see how much you are sizing. A .246 bushing may not size to .246...after spring back.
thanks for the heads up on the wilson trimmer, i had no idea that they did not use a pilot. i would love to have a nice powered trimmer like the gracey or giraud but the cost of varget these days is braking the bank.