Colt Manufacturing AR-15/M4 Upper Receiver Assembly (SP63528)

Forged flat top upper receiver assembly includes forward assist, ejection port dust cover

Upper rail is T numbered. Upper has M4 feed ramp cuts so the barrel being used must also have the proper cuts

Note: The markings on these seem to change every time we get a shipment, they may have square forging mark, they may have a keyhole forging mark, they may have something else.  They may also have Colt’s cage code or they may have no cage code.  Basically if you care how they are marked then this is probably not the upper for you.