Kaw Valley Precision Solid Stainless Steel Heavy Buffer 7.5 oz Small. 40 S&W .45 ACP and 10mm are a blast to shoot but can be tough on AR-15's internal components. Without a properly tuned blowback system you run the risk of being overly destructive on internal lower parts. Runing a blowback AR15 with a suppressor can further increase the risk for damage. Adding the KVP 7.5 oz Stainless Steel buffer is the best way to give ytheir blow back system a fighting chance. Do yourself a favor and fine tune ytheir setup for the softest shooting PCC possible. Specifications for Kaw Valley Precision Solid Stainless Steel Heavy Buffer: Manufacturer: Kaw Valley Precision Color: Stainless Steel Fabric/Material: Stainless Steel Gun Make: AR Platform Gun Model: AR-15 Gas System Length: Carbine Length Length: 4.125 in Weight: 7.5 oz Condition: New Projectile Caliber: .355 Caliber .40 Caliber Caliber: 9mm Luger 10mm Auto Features of Kaw Valley Precision Solid Stainless Steel Heavy Buffer Increases AR-15's dwell time in blowback setups Quiets action (better for suppression) - 7.5 oz - 4 1/8 OAL (Buffer spacers are NOT required) Solid Stainless Steel Construction Eliminates annoying buffer "rattle" Increases Reciprocating mass and weapon reliability Reduces wear on critical internal parts Reduces felt recoil Designed only for Carbine Length Stock and pistol kits Package Contents: Kaw Valley Precision Solid Stainless Steel Heavy Buffer What firearm models does the manufacturer say Kaw Valley Precision Solid Stainless Steel Heavy Buffer is compatible with? The manufacturer suggests that Kaw Valley Precision Solid Stainless Steel Heavy Buffer is compatible with AR-15Kaw Valley Precision KVP-7.5: Solid Stainless Steel Heavy Buffer 7.5 oz Small