Trimmer Question on Pilots

Im reloading British .303 and trimming the cases on a Lyman Hand Trimmer. I had to buy a #31 Pilot for the case mouth and found that it will not go into the mouth all the way. Only goes in half way after I have sized the cases. A #30 Pilot will fit easily but on occasion will stick in the mouth when I retract the cutter. Am I doing something wrong ? Appreciate the help.

The expander in the sizing die may be undersize, about .0015" under bullet diameter* is good. The # 31 can be turned down some if needed. Chuck it in a drill. Measure with a micrometer if you have one. The #30 may stick if the cutter head is dull or the feed rate is to high. A burr will form, holding the pilot in the case neck.

Appreciate the help...only time I ever have trouble with my reloading is with the Brit. 303 shells.