Soldiers benefit from lighter, easier to maintain mortar systems
July 19, 2011
By Ms Audra Calloway (AMC)
PICATINNY ARSENAL, N.J. - Mortar crews have started receiving new lightweight 60mm mortar systems that are approximately 20 percent lighter than previous versions.
The Program Executive Office for Ammunition fielded the Army’s first M224A1 60mm Lightweight Company Mortar Systems to 1st Special Forces Group in Fort Lewis, Wash., last month.
Eventually all former legacy M224 systems will be replaced with the new lightweight systems.
“At the beginning of operations in Afghanistan the average load for a 60mm assistant gunner was 122 pounds,” said Peter Burke, PEO Ammunition’s Deputy Product Manager, Guided Precision Munitions and Mortar Systems.
“Our program goal was to reduce the weight of mortar systems as much as we could to take some of the weight off of his back.
“These Soldiers are carrying all this weight around and are still expected to fight at the end of the day, so anything we can do lighten their load we’ve got to do,” said Burke.
Mortar systems are an indirect firing capability used to defeat enemy troops, materiel, bunkers and other infantry-type targets. The M224A1 fires the complete family of 60mm ammunition, such as high explosive, smoke, illumination, infrared illumination and practice cartridges.
The 60mm’s first major redesign since the 1970s has reduced the overall weight by 20 percent or 9.3 lbs.
“This new 60mm delivers improved portability while maintaining the existing rate of fire, range and tube life of the former system,” Burke said. “The Soldier is still carrying the same capability, it just weighs less.”
The M224A1 consists of the following components: M225A1 cannon (tube), M170A1 bipod assembly, M7A1 baseplate, M8 auxiliary baseplate and the M67 sight unit.
A mortar crew of three members distributes the mortar load with a different member carrying each item.
A team from PEO Ammunition and the Armament Research, Development and Engineering Center (ARDEC) was able to shave off the weight through a combination of using different materials and reducing the number of components.
The cannon tube on the new system is made from “Inconel,” a nickel-based material, as opposed to steel.
Inconel is just as strong as steel but significantly lighter. It also has better wear characteristics and has the potential for a longer service life, although additional testing and evaluation is required before the service life can be extended passed the current round limit.
DESIGNED FOR LESS MAINTENANCE
The bipod, which holds the cannon steady at the desired elevation and angle, was also completely redesigned.
Through changes such as incorporating the lighter, but still high performing materials of aluminum and titanium into the bipod, the team was able to reduce the bipod weight by 17 percent.
In addition to a reduction in weight, the bipod’s new design requires less maintenance.
One of the major upgrades included gears that do not need to be lubricated by grease and oil.
“This reduces the amount of maintenance to the system,” Burke explained. “So instead of squirting grease in there and then worrying about dust and sand mixing with it and gunking it up, now we’re using Kevlar and other self lubricating material coatings so there’s no grease required and the components still move like they’re supposed to move.”
The Kevlar is reinforced with composites and protective coatings infused with lubricants that eliminate the need for external lubrication.
Another improvement to the bipod is the addition of self-locking legs that lock in both the open and closed position. The former system had a chain that held the legs in the open position. It was also used to chain the legs together for transportation.
“Now, when the legs fold in they lock in place so they don’t flop around and they don’t have to be wrapped up with fiber straps or a chain anymore,” Burke said.
A cross-level bubble has also been built into the bipod to assist the Soldiers in positioning the cannon to achieve accurate leveling needed for proper targeting.
Soldiers will see increased mobility with the new light weight system, Burke said.
During testing, a crew participated in a cross-country course carrying the lightweight M224A1 and the former M224. Overall, when the crew carried the lightweight system, crew members took 11 percent less time to finish the cross-country course.
“It was quicker because it weighed less. And the crew had reduced fatigue. When we asked them at the end of the course, they said they felt less tired with the lighter weight system,” Burke said.
Burke said his team is excited to be fielding the new system and that other Soldiers are looking forward to the lightweight 60mm mortar system.
“The Soldiers who have seen it at trade shows can’t wait to get it,” Burke said.
“They depend on it, they always carry it around, and they’re looking forward to getting something lighter.”
PEO Ammunition is scheduled to begin fielding a lightweight 81mm mortar system to troops in early 2012.
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