im using the lee case trimmer. it was working great till now. i would take a fired case, resize and deprime it, trim it to length, and throw it back in the tumbler for cleaning, then load it. worked great for years. the trimmer pilot went right into the resized cases no problem at all. then all of a sudden the trimmer wouldnt go into the resized cases. so i tried the trimmer in some 06 resized cases and it went right in. same neck diameter right. so i went and bought a new set of dies thinking that the die was the problem and sure enough everything worked exactly as before. then after 100 rounds or so the trimmer die wouldnt go into the resized cases of the new dies. when i took the dies apart it looked like the expander portion of it had worn down and when i put the calipers on it it was significantly smaller than expected. almost as if the brass had worn it down - very odd.