HAO sent some pics of their Gen I and Gen II Colt M4A1 receiver sets for Systema PTW. As usual, these sets are CNC’d from 7075T6 billet. Trades are stamped (deeply, by the looks) and the serials are nicely engraved.
The pics aptly demonstrate the generational differences between the two types, with the Gen II being the more modern type.
Available to buy direct from HAO or via HAO dealers.