This 9mm upper came with my M16. I test fired it one time with a friends RR and one of the included STEN mags with no problems. It's a turn key setup with two STEN mags, a 50 round Lanchester mag, and the magazine block. This is a complete upper. The upper has complete full auto internals. All NFA rules apply.
Asking price for the whole package is $650 plus S/H of $15.