From the onset, Windham Weaponry has had one goal: to build the finest AR type rifles in the country. All of their rifles are built with 4150 Chrome Moly Vanadium steel barrels which are chrome-lined for long wear and ease of maintenance and 7075 T6 aircraft-grade aluminum receivers with a durable black hard coat anodize finish. Their Varmint Exterminator utilizes a gas-impingement system that's housed in an M4-A4 flattop upper receiver with picatinny optics blocks that make scope-attachment easy. The rifle's bolt is made of Carpenter 158 Steel and its 20" stainless steel barrel is fluted and given a 1 in 8" right-hand twist. Its skeletonized stock is extremely light and comes standard with sling swivel studs. Hogue rubber grip. 5-round magazine. Lifetime warranty.