What is it ?

[shooterg]

Came in a box of reloading stuff. Don't even know of the pieces go together, but the holes in the black pieces fit onto the shaft. It's definitely a well made whatchamacallit !

[oldscool]

Looks similar to a Sinclair bullet seating depth tool.

[429421Cowboy]

I also am thinking it has to do with measuring maximum OAL for seating out into the throat.

[novalty]

I think oldscool nailed it! Looks like a Sinclair Seating Depth tool (http://www.sinclairintl.com/reloading-equipment/measuring-tools/bullet-seating-depth-accessories/sinclair-bullet-seating-depth-tool-prod35491.aspx).

[shooterg]

You guys nailed it ! The Sinclair site even has a video showing how to use it. Comes with one bolt guide doohickey for most standard bolt guns - 2 guides with this one but I have no idea what the other fits. Looks to be about $50 retail for what I have - now I can pass it on for half that since I now know what it is.

Thanks - I KNEW somebody here would know !