The Ranger 5 RBP (Reduced Back-Pressure) improves upon the original Ranger 5 design with the inclusion of AAC's new Double-Helix Gas System aimed to reduce gas blowback without sacrificing durability. The Ranger 5 is full-auto rated ensuring long-lasting durability even under extended strings of rapid fire. This model features a custom Black Alphatek non-reflective coating designed to reduce I/R signatures and is designed for use with .22 caliber centerfire cartridges. Attachment to a rifle requires the use of AAC's 1.375-24 Universal Mount and must be purchased separately. *Sound reduction ratings are approximate based on measurements by the manufacturer and may vary depending on firearm setup and environmental factors.*