Originally Posted by Ricochet
Now that I'm looking at it, it looks like a buffer tube plug for an AR. Remove your rear stock to shorten up the gun, and the ring is for a sling. Maybe it's too small.
I know what you mean but it is too small for that purpose. It fits the Diablo Flash hider perfectly. The threads go in and the Diablo has a groove cut out that fits the rim of the unknown item. Beautiful keychain, LOL.