STAG ARMS 15 BCG, BOLT CARRIER GROUP, AR15, 5.56/.223/300 BLK, NICKEL BORON, BLEM vs Standard

SHOW AND TELL: STAG ARMS 15 BCG, BOLT CARRIER GROUP, AR15, 5.56/.223/300 BLK, NICKEL BORON, BLEM vs Standard

Link to item description : https://www.stagarms.com/products/stag-fire-arm-parts/upper-components/bolt-carrier-group-5-56-223-300-blk-nickel-boron-right-handed-stag300755.html

Wikipedia article on Stag Arms : https://en.wikipedia.org/wiki/Stag_Arms

Wikipedia article on Closed bolt : https://en.wikipedia.org/wiki/Closed_bolt

Wikipedia article on Electroless nickel-boron plating : https://en.wikipedia.org/wiki/Electroless_nickel-boron_plating