PWS Enhanced Mil-Spec Buffer Tube (PWS Fully licensed product) Features: QD Sling Swivel Adapter (Sling Swivel not Included) Aluminum T6 6061 Matte Black About PWS Mil-Spec Enhanced Buffer Tube: (link) The PWS Enhanced Buffer Tube is the first major upgrade and improvement to the buffer tube in years! This one piece billet buffer tube is CNC machined out of solid 7075 aluminum in order to gain lightweight strength and reliability. This unit is specifically designed to work fit the HK416, but will also fit all mil-spec lower receivers. The Enhanced Buffer Tube will resolve any carrier tilt symptoms exhibited by a short stroke piston AR and will reduce felt recoil. Details The most notable features on this buffer tube include: 1. One piece construction eliminating the castle nut and ensuring that when installed, the buffer tube cannot become loose. 2. Attachment system automatically indexes the buffer tube perfectly straight. 3. The bottom of the interior buffer tube extends a lip into the receiver, supporting the bottom rear of the bolt carrier, reducing the carrier tilt present in some piston systems. 4. A dead blow buffer is securely installed in the rear of the buffer tube to reduce carrier speed by an average of 10%, and dramatically reduce felt recoil. 5. Two QD sling swivel attachments are machined into the front of the buffer tube allowing ambidextrous connection of your QD slings. 6. The buffer tube is fluted to allow debris to be pushed out of the way, and a drain hole has been placed in the bottom of the tube, allowing for draining of water when the rifle is parallel to the ground. About PWS: (link) Primary Weapons Systems, Inc (PWS) is a Federally-licensed firearms manufacturer located in Boise, Idaho. PWS is the designer and manufacturer of the MK1 and MK2 series rifles and uppers in addition to a complete line of flash suppressing compensators such as the FSC556, SM556, FSC30, and more. PWS develops items based on real world requirements with the goal of redefining accuracy and performance in the piston-driven platforms.