Nice batch Mark!!
Sometimes when I make these I find that the OD of the nib end of the shell is a few thousandths
oversize. I drilled a .330'' hole (OD of slimline nib) in the center of a piece of wood 1'' x 1/2''
and a few inches long and cut it in half lengthwise thru the middle of the hole.
With the shell spinning in the lathe squeeze the two halves of the wood onto the nib end of the shell.
You can change the OD pretty quick and accurate this way.
If you make it too small insert a shallow tapered dowel to enlarge it.