Not for a standard ar15 upper receiver - CMMG 7.62x39mm Non-Threaded Barrel

This barrel doesn’t fit a standard AR15 upper receiver. The barrel is much bigger where it fits into the receiver. Apparently CMMG makes a certain upper receiver to fit this barrel. I already purchased all the upper components to build this upper so I returned this barrel for a standard AR15 barrel. So I don’t recommend buying this barrel until you do your research on what receiver and handguard you will need.