COLT UPPER RECEIVER FOR SALE FOR DUMMIES

  The magwell engraving has changed, and Colt has rebranded all their carbines as "Carbine" and no more marked M4 Carbine.  This can be the only modify to your product.Good news, MK18 upper arrived currently from Principal Arms.  Looks wonderful.  I want to finalize the remaining parts I must get to complete this Make and make use of some Black