colt 727

The Colt Model 727 was an early commercial "off-the-shelf" carbine used heavily by U.S. Special Operations Forces (SOCOM)—including Delta Force and Navy SEALs—before the U.S. military officially adopted the XM4 and standardized it as the M4 in the mid-1990s

Often called the "M16A2 Carbine," the 727 is the the transitional 1980s predecessor to the standard M4. While both feature 14.5-inch barrels, the 727 uses a fixed carry handle with an A2 sight and full-auto, whereas standard M4s utilize flat-top receivers for optics and offer three-round burst.