M&amp;P15 piston with MOE Grip and PRI sights.
Other version without background from: File:MP15.jpg
<a href="//commons.wikimedia.org/wiki/User:Coldbolt" title="User:Coldbolt">Coldbolt</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>