Wilson Combat The AR9 Optimized Recoil System. This drop-in system is compatible with the Wilson Combat AR9 and similar short-stroke blowback 9mm AR carbines. The AR9 Optimized Recoil System comes with three full-size 1911 recoil springs (recoil spring weights 15 17 and 20 pounds) to tune your bolts speed to optimum reliability. This buffered system will reduce wear and tear on your AR9 and provide you with a softer recoil impulse for faster follow-up shots and is ideal when tuning your gun for competition use. rodPuced of high-quality fully hardened stainless steel with no pins or fasteners to fail the Optimized Recoil System will stand up to years of hard use. The black polymer buffer cushions the action for smoother shooting. (Replace buffers when they become worn or damaged. Extra buffer included.) Comes with 3 recoil springs included to tune to ideal reliability. Specifications for Wilson Combat The AR9 Optimized Recoil Systems: Manufacturer: Wilson Combat Fabric/Material: Stainless Steel Black Polymer Gun Model: AR-9 Condition: New Features of Wilson Combat The AR9 Optimized Recoil Systems Tuneable to your specific ammunition. Smoother feel without the grating sound of a standard action spring. Three recoil springs (1517 20 pound weights) included to tune your gun for your specific load. Black polymer buffer cushions the action 2 included. Use 1 now then replace when buffer is worn or damaged. Package Contents: Wilson Combat The AR9 Optimized Recoil Systems What firearm models does the manufacturer say Wilson Combat The AR9 Optimized Recoil Systems is compatible with? The manufacturer says that Wilson Combat The AR9 Optimized Recoil Systems is compatible with AR-9Wilson Combat TR-AR9RS: The AR9 Optimized Recoil System