Threaded hole is blind. Hole could have been drill clear thru but no need. Made these from 12L14, could have used 1018 just as well.
Hole end of smaller diameter section was for a center, no other purpose for it to be there.
Very close.
Pegs to hold Dillon 550 shell plates. They will be screwed to a board cut to fit in the bottom of a plastic bin. Lid keeps the dust off. I was keeping them in a drawer but they were rattling around and the drawer was getting crowded.