Nylon Screw on Dillon Power Drop

There's a chubby, off-white nylon screw (at least I think it's a screw) on the Dillon powder drop, could someone tell me what it does?
Couldn't find any info on the interweb.

If this is what I think, the only function it carries is preventing insert from drifting when small powder bar is used.  It is not screw, but rather sort of plug that can be pulled up.
AP

Yep what PhotoEscape said, it is just a pin.  When you use the small powder bar for pistols there is a spacer that goes above it and is held in place by the small powder bar and the pin.
- Dave

Thanks for the speedy replies!

Lee at UniqueTek suggests replacing it with a screw. Drill and tap as I recall. The plastic piece can apparently become loose, etc.