As with any weapon system, there are costs and benefits associated with the GAU-19. It is heavier and more complex than the M2 .50 caliber machine guns and M-19 grenade launchers currently mounted on U.S. HMMWVs, for example, and requires an external power source to fire. It also consumes ammunition at a tremendous rate, which can be a problem in sustained engagements. On the other hand, it provides an absolutely devastating amount of firepower, and has a greater effective range than those other weapons.