WHAT DOES COLT 20 INCH CLASSIC UPPER MEAN?

The up to date M16/M4 rifle is built around the notion of modularity. The entire BCM® flat leading uppers element a USGI variety laser etched T-marks to deliver addressing to the remounting of tactical components including optics, laser sights, and many others.Which is my regular luck. No funds when some thing I would like is for sale and not for