Patriot Ordnance Factory Patriot Ordnance Factory, Enhanced Anti-tilt Buffer Tube, Fits AR-15, Black 342 The POF Mil-Spec 7075-T6 aircraft aluminum Anti-Tilt Buffer Tube uses carrier cradle extensions to ensure that the bolt carrier is always supported by the buffer tube" even when the bolt is forward. This prevents carrier-tilt and premature wear on the buffer tube. Thusly" the buffer-detent button doubles as a lock that stops the buffer tube from rotating and becoming loose under extreme operation conditions. POF-USA's designing also features three (3) extra drain holes for marine environments.