ID Part

[A-37]

Found this in my misc. gun parts box and I don't know what it is.

Steel, 5/8" OD, knurled, no internal threads (smooth 1/2" bore).

 

[sceva]

It's a cartridge case deburrer. I believe a Lee.

It will deburr both inside (cone end) and outside ( the hollow end) after trimming cases.

 

[A-37]

Right on! Thanks.

I can use it to deburr my K&S brass hobby tubing.

 

[Ivan the Butcher]

I used one like that one time! Absolutely wears out your thumb, to the point of cramps at around the 8th case! I use one that is powered by an electric screwdriver. (between 15 and 30 RPM, a drill is too fast!)

Ivan

 

[soFlaNative]

Without knowing the size I would have guessed a valve stem cover with stem remover / tightener.