I recently got a small handle Lyman 310 on Fleabay with full set of dies for 32 acp. In the box was also a couple other items. There were two extra primer die plungers. One just the "stem" and the other one with the spring. The one with the spring is for small primers (not sure if pistol or rifle, haven't checked) and also has a cup like your standard hand seating tool like a Lee or RCBS. I can't figure out how to swap these out in the die. There is a very small pin retaining the spring loaded plunger in the die. Is there a trick to this? Thanks.