According to Sam Newland, Quick Reaction coordinator for the U.S. Army’s Natick Soldier Research Development and Engineering Center, “As a single gunner, that’s lead on target for 500 continuous rounds of ammunition fired in bursts. It just made it more efficient for an individual gunner to execute his mission in that way. It started out as a DIY project, because soldiers on the battlefield needed a capability based on changes in the way they operated. As a result of that, they built it themselves with legacy equipment.”
Will this end up as part of the official Army gear? Only time will tell, and there are some definite advantages to it, not to mention increasing the chances of you surviving on the battlefield as you rain lead on the enemy lines without too many pauses in between.