Almost any Free Float rail will fit hte Norinco, and most drop-ins will also fit IF you change out the handguard end-cap to a proper in-spec one.
More importantly though, the Norinco is a $700 AR and if you are going to add a $200+ rail system to the rifle, why would you not instead get a better AR?
Let me put it to you this way.
Aero Precision lower: $145
Aero Precision upper: $115
LPK & UPK: $120 Brownells
Buffer assembly: $45 Armseast
Stag full-auto bolt: $175
sj hardware barrel: $220
Low profile gas block and gas tube: $50
Buttstock: $30 or so in the EE?
That's only $960, or $260 more than a Norinco and you get an all north-american made AR, everything except the free float handguard - which will run you about another $200 taxes in if you order a decent YHM diamond series HG from fabsports - a tad more if you get a YHM tube end-cap from Brownells for aesthetics.
Or if you want the M4 fixe front sight look, get a $330 complete chrome lined M4 barrrel assembly from ATRS instead of the S&J hardware barrel.
