By Anniston Army Depot Public AffairsFebruary 6, 2019
ANNISTON ARMY DEPOT, Ala. -- Two Anniston Army Depot employees participated in the testing of a new M777 prototype at the Yuma Proving Ground in January.
Bob Rosch, a mechanical engineer for the depot's Directorate of Production Engineering, and Jamey Smith, an artillery mechanic, traveled to Arizona to calibrate the slipper pads on the prototype, one of the steps in testing the experimental weapon.
The slipper pad calibration process currently in use was established in 2015 at ANAD to enable M777 medium, towed howitzers to be mated with a new cradle after their original cradle was damaged.
The procedure uses a laser tracker to accurately measure the elevation of the howitzer's barrel through its full arc of motion. On a typical M777, the arc is from 0 to 1,275 angular mils. For the new prototype, with its longer barrel, the arc is 0 to 1,200 mils.
According to the Towed Artillery Systems Program Management Office, the M777-Extended Range howitzer is an Army and Marine Corps funded effort to increase the range of the weapon through a 55-caliber tube.
A more efficient muzzle brake minimizes blast over pressure on the gun crew, while a reinforced recoil yoke allows for higher firing loads.
The tube's length means a need for longer road arms to compensate.
Rosch and Smith said additional weight was also needed to anchor the gun, ensuring it remained motionless during calibration.
"We added weight to secure the gun and reduce movement," said Smith. "The barrel is longer, so there was a concern its weight would cause some shift."
The procedure was successfully adopted for use on the new experimental gun.
PM-Towed Artillery Systems says the Long Range Cannon is a project funded in collaboration between the Army Rapid Capabilities and Critical Technologies Office, the Army and the Marine Corps.
The program seeks to accelerate the M777-ER effort while demonstrating accuracy improvements to long range fires with a Projectile Tracking System.
"A complement to the baseline LRC effort is the integration of a full fires network infrastructure, the Location and Azimuth Determining System, and the ammunition required to achieve current and future long range precision fires objectives," said Capt. Luis Gaitan, assistant product manager for the Long Range Cannon/ M777ER.