Must have parts for your Colt build! These are genuine Colt manufactured M16A2 style upper receivers for the M16. Attach most M16/M4 style braces or stocks to your favorite MAK-90 rifle! Our M4-MAK Stock/Brace adapter is very unique in the way it mounts to the rifle! Colt M4 Carbine Upper Receiver, Government Contract Samples, 5.56x45 *NEW* Sold Individually. THIS WILL NOT WORK ON MILLED RECEIVER MAK-90. THIS WILL NOT WORK ON SLANT CUT REAR RECEIVER MAK-90, YOU WILL NEED M4-MAK-S. MAKO FAB Defence AKM/AK-47/74 Stamped receiver M16/M4 Fixed Stock quantity. MAKO FAB Defence AKM/AK-47/74 Stamped receiver M16/M4 Fixed Stock $ 119.99. Home / AKs / AK Stocks / MAKO FAB Defence AKM/AK-47/74 Stamped receiver M16/M4 Fixed Stock.Stock counts as one US compliance part for 922(r). Designed to fit most common stamped AK receivers without modification via a unique wedge block, the durable injection molded polymer Zhukov-S Stock redefines the human interface with the AK platform. The Zhukov-S has right-side folding for compatibility with side-mounted optics.Most are take-offs from new guns or upper receiver groups. Colt M4 Upper Receiver, "C" marked (raised) Factory new (old stock), Colt upper receiver with "C" marked on the left side, raised up, as this mark is from the original forging.