It appears too small to be a reloading press... The item seems to be only a couple inches long.
Here's a pic of a simple reloading press.
The first thing that came to mind was a bit of toilet hardware... but that was just first impression.
The chain's not heavy enough for it to be a lock of any kind. Looks like it's just there to keep a couple of different parts from wandering off.
I think that the cylinder opens (unscrews or something) and the chain keeps it from going anywhere. There's probably an open space inside that holds whatever it's meant to. The ring is there so you can attach it to something else (like with a padlock).
But of course that's just guesses.