For almost 30 years the M-249 Squad Automatic Weapon has been the go-to light machine gun for U.S. Army infantry squads — and Marine Corps squads, too, until recently. And now you can walk into your local gun shop and purchase a semi-automatic M-249S SAW, a replica of the fully-automatic M-249. FNH USA, the U.S. subsidiary of Belgian weapons manufacturer FN Herstal, began selling the semi-automatic version of the weapon on the civilian market in November as part of their new Military Collector Series, which also includes replicas of their M-4 carbine and M-16 assault rifle. Fans of black guns...