Thread: What causes this

Originally Posted by veitnamcam

Seating die set too low or brass needs trimming.
Trim all brass to same length put one in shell holder put ram right up. Wind die down till it touches neck and wind back up half a turn. Lock it and adjust seating depth from there.

What VC said, looks like your seating die iis contacting your brass. Surely you must feel the pressure difference when this happens? Is it occuring all the time or only on the odd case? if its the latter it sounds like its probably time to trim your brass.