Picatinny Arsenal engineers have been working to create a longer, newly modified M777A2 howitzer that has the potential to double the range of current M777 artillery systems. Charged with developing technology to extend the range of all 155mm artillery, the Extended Range Cannon Artillery (ERCA) project is funded by science and technology office at the US Army Armament Research, Development and Engineering Center (ARDEC).
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 program is funded program by the Army and the Marine Corps.
With nearly 1,000 pounds (453 kg) added to the system’s overall weight and an additional six feet (1.82 m’) of cannon tube, the demonstration is taking place to give the Soldiers and Marines more confidence that the gun will still meet all of its mobility requirements.
The Army Program Manager Towed Artillery Systems, (PM-TAS) has already demonstrated a modified M777A2 Howitzer with an integration kit for the mass mock-up of the modified XM907 ERCA cannon at Yuma Proving Ground, Arizona. Follow-on mobility testing will be conducted at Aberdeen Proving Ground, Maryland, to document the changes in mobility from a standard M777A2, if any.
After the ERCA program, the M777ER program is engaged in making sure that ERCA’s system is suitable for the M777 system.
The final ERCA system will be demonstrated with an M109A7 system, which is the Paladin self-propelled howitzer.
“The ERCA program is developing the cannon to give it more range. PM-TAS is doing the demonstration to the Marines to show how it would look, feel and move when integrated into the M777A2 carriage,” said David Bound, M777ER Lead, Artillery Concepts and Design Branch, which is part of ARDEC. At this stage the demonstration will not include firing the weapon, but will show how the gun responds when it travels and how it feels when the crew interacts with the controls. “Right now (the M777) can shoot about 30 kilometers, but once all of the upgrades are complete it will be able to shoot about 70 kilometers,” said Bound.
“The visual prejudice we are up against is that it looks like it may tip over with all that extra cannon. We are trying to increase confidence that the M777 is an acceptable candidate for an extended range upgrade” said Bound. In efforts to ensure that the gun will meet all of its requirements, a mobility cannon tube was created.
The mobility tube consists of an old 52-caliber tube that was modified to fit into an M777A2 at the weight of the XM907. Additionally, grooves were added to the exterior of the tube to allow Picatinny engineers to hang weights at different positions, enabling them to move the center of gravity of the weapon forward or rear.
This cannon will allow the Army and the Marines to assess the impacts to the M777 and how it’s operated as the ERCA program optimizes the cannon design.
“The weights allow the Center of Gravity to move and get to the point where we can start towing this around as the configuration of the tube changes as the ERCA figures out what they want to do because it’s in flux right now,” said Bound.
“We are able to replicate how that tube reacts in the system using the different weight configurations. Then, we can hook this up to a truck so we can see what the users can expect from a human-factors point of view of how much harder it is to elevate, traverse back and forth, and what the trucks are going to see as they tow the system around,” said Bound.
