The Maxim Defense Industries MDX 505 PDX SCW PDW Brace Upper Kit The buffer system/bolt assembly allows this AR pistol to be 18.75 inches with the stock collapsed. These AR15 Upper Receivers are a cut above what you get anywhere else. The Maxim SCW system of the PDX Brace Upper Kit cuts down the stock length to 4″. Interchangeable buffer weights give you maximum performance and versatility without sacrificing form and functionality. If you're looking for a quality build for your AR15, you want to get the Maxim Defense Industries MDX 505 PDX SCW PDW Brace Upper Kit.Specifications for Maxim Defense Industries MDX 505 PDX SCW PDW Brace Upper Kit:Manufacturer:Maxim Defense IndustriesOverall Length:14 inBarrel Length:5.5 inWeight:5 lbHandguard Type:Free-FloatMuzzle Device:HatebrakeFabric/Material:6AL-4V Titanium, 6061 Aluminum, 7075 Aluminum, 17-4 Stainless SteelFinish:Type III Hardcoat AnodizedAdditional Features:PDX/SCW CompatibleGun Rail:PicatinnyGun Model:AR-15Country of Origin:USAFeatures of Maxim Defense Industries MDX 505 PDX SCW PDW Brace Upper KitFEATURES:HATEBRAKE installed under the handguardM-slot compatible handguardMilitary grade materials 6Al-4V Titanium, 17-4 Stainless Steel, 7075 and 6061 AluminumSCW Buffer-carrierHK height rail for a more rigid upper receiverMilitary tested Rapid Deploying PDW stockFUNCTIONS:Optimized Personal Defense Weapon kitIncreased reliability due to included HATEBRAKEOptimized low flashDesigned to be installed on any Mil-Spec lower receiverPackage Contents:Maxim Defense Industries MDX 505 PDX SCW PDW Brace Upper KitPackage Contents:Maxim Defense Industries MDX 505 PDX SCW PDW Brace Upper KitHATEBRAKE installed under handguard 1-2 MOA accurateM-slot compatible handguard Military grade materials 6Al-4V Titanium 17-4 Stainless Steel 7075 and 6061 Aluminum SCW Buffer-carrier HK height rail for a more rigid upper receiver Military tested Rapid Deploying PDW brace.Maxim Defense Industries MXM-47814: MDX 505 PDX SCW PDW Brace Upper Kit, 7.62x39, 14in, Hate Brake, 5/8-24 Thread, 5.5in Barrel, Type III Hardcoat Anodized, Arid EarthMaxim Defense Industries MXM-47815: MDX 505 PDX SCW PDW Brace Upper Kit, 7.62x39, 14in, Hate Brake, 5/8-24 Thread, 5.5in Barrel, Type III Hardcoat Anodized, BlackMaxim Defense Industries MXM-47816: MDX 505 PDX SCW PDW Brace Upper Kit, 5.56 NATO, 14in, Hate Brake, 1/2-28 Thread, 5.5in Barrel, Type III Hardcoat Anodized, Arid EarthMaxim Defense Industries MXM-47817: MDX 505 PDX SCW PDW Brace Upper Kit, 5.56 NATO, 14in, Hate Brake, 1/2-28 Thread, 5.5in Barrel, Type III Hardcoat Anodized, BlackMaxim Defense Industries MXM-47828: MDX 505 PDX SCW PDW Brace Upper Kit, 300 BLK, 14in, Hate Brake, 5/8-24 Thread, 5.5in Barrel, Type III Hardcoat Anodized, Arid EarthMaxim Defense Industries MXM-47829: MDX 505 PDX SCW PDW Brace Upper Kit, 300 BLK, 14in, Hate Brake, 5/8-24 Thread, 5.5in Barrel, Type III Hardcoat Anodized, Black