Started the process of loading around 200 .243 WSSM cases yesterday. All are Winchester premium nickel cases. Just finished resizing about 400 .223 in brass cases last week. The RCBS trimmer worked fine and had a nice pile of shavings under the cutter. This is my first time trimming nickel bottle neck cases. I've had and reloaded/shot them several times in the past as they didn't exceed the maximum case length of 1.670. Of the 200 that were polished, about 40 were over max length by a couple thousands of an inch. Once the electric/pneumatic trimmer was set up, got started and either the cutter got dull doing the .223, or the nickel cases are really tough. No cutting was going on. Had to put pressure on the motor head to "burnish" the case to length with a huge roll around the mouth of the case. Don't know if they are too tough for a high speed steel cutter or what, so ordered a carbide cutter today. Anybody experience the same with nickel cases?