What are they?

[GOPHER SLAYER]

Could someone tell me what these shell holders are for? The threaded post is 1/2 inch with fine threads.

[Lightning22]

Lee neck trimmer?

[turtlezx]

lee case length trimmers. Should be pilots that go with it that thread into a cutter to trim cases to length
You chuck the stem into a drill

[GOPHER SLAYER]

Thanks.