The ERCA program evaluates the introduction of a longer barrel, developed for the XM907 Common Cannon Assembly Support system, as well as the XM1113 rocket assisted projectile and XM654 supercharge, an autoloader and new fire control system.
The M777 can shoot about 30 kilometers, but once all of the upgrades are complete the M777A2 will be able to shoot about 70 kilometers
The newly modified M777A2 howitzer has the potential to double the system's current artillery range. Benet Labs designed the tube and Picatinny designed all of the carriage modifications. Photo by Erin Usawicz.
SOURCE - Defense Update