The Fulfilled Potential Of The AR-15/M16. One of the most tested and proven weapons systems in the world achieves ultimate refinement with the introduction of the SIG516 rifle. With its ambidextrous selector switch, chrome-lined, 1/7 twist nitride-finished, military grade barrel and adjustable, four-position gas regulator, the SIG516 incorporates all of the most desirable mechanical improvements. Add to these a free-floating quad rail forend and barrel, and you have the most advanced, versatile AR-based rifle available. Comes with Mag-Pul MOE stock & grip, bayonet lug, Sig STS-081 red dot w/ picatinny mount, qd attachments on lower receiver, ambi-mag release, qd mounting point on rail as well.

For anyone that owns an M16, registered receiver or sear- the upper does fit to a standard mil-spec lower.