Guntec usa ar-10 mil-spec buffer tube set, .308 cal - Guntec USA AR-10 Mil-Spec Buffer Tube Set, .308 Cal

This unit has a 3.8oz buffer. It would not cycle my rifle. I had to make purchase of a 5.0oz buffer and use an Aero Spring to make it go like it should. This might have worked if the buffer were heavier.