The M107A1 uses a lightweight aluminum receiver along with additional weight saving improvements to create a rifle that weighs 5 pounds lighter than the original M107. The rifle is designed from the ground-up to be suppressor ready and features new bolt carrier group and muzzle brake designed to interface with Barret's QDL series of suppressors. A titanium barrel key and chrome-lined bore adds to the rifle's durability and reliability, while a full length Picatinny rail allows for a wide range of optics and targeting accessories to be mounted. The S variant features a steel upper receiver in place of the traditional aluminum receiver. This model is chambered in .50 BMG and features a 20-inch barrel. One 10-round magazine is included along with a bipod.