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 Aluminum Receivers with a durable black hard coat anodize finish. The SRC utilizes a gas-impingement system that's housed in an M4-A4 flattop upper receiver. The R18SFST-308 model adds a Midwest Key Mod 15" handguard and a full-length picatinny top rail. The rifle's bolt is made of Carpenter 158 Steel and its 18" fluted medium profile barrel has an A2 flash suppressor and a 1 in 10" right-hand twist. Other notable features include: a 6-position telescoping buttstock, a Hogue overmolded grip, and a manual safety lever with indicator markings on both sides of the receiver. Each rifle ships with a hard plastic carrying case, a web sling, and one 20-round Magpul PMag magazine and carries a lifetime warranty.