The Colt M4 OPS is a "true to the original" replica of the current version of the M-16 machine gun issued to special forces operators in the US. Like the original, the replica features a carbine length barrel, collapsible stock, and quad skeleton forend with accessory rails. Like the military issues, the upper and lower receiver is made of high quality aluminum. The Colt M4 Ops Semi-Automatic Rifle in .22 LR is manufactured exclusively by Walther under license from Colt. It is the only genuine Colt tactical rimfire replica available in the world. Additional M4 OPS features include: an adjustable telestock, a rear sight that's adjustable for windage and elevation and removable, a front sight that's adjustable for elevation, a CNC-machined tactical railing with rail covers, a threaded muzzle, a bolt catch, and a steel flash suppressor.