The KynSHOT RB5000L Hydraulic Recoil Buffer is optimized for use with light loads, including subsonic ammunition and .300 BLK. The RB5000L has seen heavy use with civilian competition shooters and law enforcement personnel. This buffer has patented damping technology to absorb the shock of impact from the bolt carriers rearward motion and to prevent bolt bounce as a new cartridge is chambered. This model is made lighter and requires less force to cycle than the standard AR-15 KynSHOT Buffer. This is intended for soft cycling or under gassed guns that will not lock back on the last round with the standard carbine hydraulic buffer or heavier buffers. .300 BLK guns running exclusively supersonic ammo may be fine with a standard hydraulic buffer if the bolt cycles firmly and has proper ejection placement. Specifications for KynSHOT AR-15 5.56/.223 Sub-Sonic and 300 Blackout Hydraulic Recoil Buffer: Manufacturer: KynSHOT Color: Silver Finish: Stainless Fabric/Material: 17-4 Stainless Steel Gun Make: AR Platform Gun Model: AR-15 Gas System Length: Mid Length Diameter: 0.69 in Length: 3.64 in Weight: 4 oz Additional Features: For 300BLK Applications Condition: New Caliber: 5.56x45mm NATO, .223 Remington Country of Origin: USA Gun Type: Rifle Features of KynSHOT AR-15 5.56/.223 Sub-Sonic and 300 Blackout Hydraulic Recoil Buffer Drop-In Replacement Reduce felt recoil Improve reliability Reduce bolt carrier speed Reduce wear on parts Reduce shock and vibration to optics Suppress bolt bounce Decrease sight movement Smoother operation Faster shot recovery time Military grade materials and manufacturing Package Contents: KynSHOT AR-15 5.56/.223 Sub-Sonic and 300 Blackout Hydraulic Recoil Buffer