Apr 21, 2010

Making the Army’s First Titanium Machine Gun

First adopted by the Army in 1977 as an armor vehicle mounted secondary weapon system, the M240 7.62mm medium machine gun series has long been a dependable workhorse. After Army and Marine infantry units began employing the M240B in the mid 90s, the popularity of the gun soared as it became known for reliability, durability and low maintenance requirements. Despite its success, however, Soldiers still pointed to the added weight and length of the M240 as compared to its infantry squad predecessor, the M60. This feedback inspired the remedy which has arrived today in the titanium built M240L.

“We’ve taken a great gun and made it better,” said COL Douglas Tamilio, Project Manager (PM) Soldier Weapons for PEO Soldier. “The M240L meets all the standards of the M240B, but in a significantly lighter package. More than ever, we need weapons in the fleet that reduce the burden on our Soldiers who have to operate with heavy loads in extreme terrain.”

Manufacturing a Titanium Gun
The concept for the M240L originated on the drawing boards of PM Soldier Weapons at Picatinny Arsenal and the M240 manufacturer. The organizations collaborated to develop a variant of the M240B that would reduce the weapon’s weight by four to seven pounds without compromising the gun’s operational characteristics and outstanding reliability. To achieve this objective, engineers started evaluating high-performance, lightweight materials and alternative manufacturing methods.
After much research, engineers ultimately settled on using a titanium alloy as the primary metal for the M240L. Known as a “space age” metal, titanium is especially known for having the highest strength-to-weight ratio of any metal. The new titanium parts on the M240L include the receiver body, the front site post, and the carrying handle.
Working with titanium called for adjustments to the manufacturing process. The lighter weight metal takes longer to machine than steel and requires more frequent replacement of tooling bits. Early on, engineers experimented with welding the titanium components together, but ran into warping issues. The final solution rested in using stainless steel rivets, which are more pliable than titanium and resist corrosion when in contact with titanium.
Once assembled, the weapon needed a protective coating to preserve the metal. Steel weapons typically get a phosphate coat and are subsequently oiled, but the titanium receiver required a completely different process.
“Titanium alloys don’t actually rust, they gall, causing the surface to become rough and deformed over time,” explained Thomas Walsh, M240 Product Management Engineer. “To solve this challenge, we researched coatings that could protect the metal under extreme operating temperatures. We found success with a chrome carbo-nitride coating used for industrial, high-heat applications. A ceramic-based top coat is added to complete the process.”
The final product weighs in at just 22.3 pounds, nearly five pounds lighter than the M240B. To those familiar with the M240B, there is hardly a discernible difference in the new gun beyond its lighter weight. The M240L meets all the operational requirements of the original while maintaining the same high standards of reliability and durability.

A New Weapon on the Battlefield
This January, PM Soldier Weapons delivered 50 M240Ls to dismounted Army and SOCOM units for operational assessment. Starting in September, more ground pounders in Airborne, Air Assault, and Special Forces units can look forward to receiving the new guns as production gets underway for the Army’s initial purchase of 4,500 weapons. Early Soldier performance tests indicate that Soldiers will like what they see.
In Aberdeen Proving Ground studies, Soldiers carried the M240L significantly faster than the M240B on the cross country course and turned in improved completion times in obstacle course runs as well. Soldiers also rated the majority of the mobility and user acceptability characteristics for the M240L significantly higher than the M240B.
Future enhancements to the M240L are already underway. This spring, testing will be completed on the short barrel, which will reduce the gun’s overall length by four inches and bring the weapon’s weight down to just 21.8 pounds. In addition, a collapsible buttstock for all M240 series guns will be available by late summer. Finally, an adjustable bipod is in the works.
“As we continue to listen, we continue to learn,” said COL Tamilio. “The titanium M240L represents a leap in weapons technology inspired by Soldier feedback. The lessons learned from this program will undoubtedly benefit future weapons systems that will maintain our continued advantage on the battlefield.”

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