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Army working on next-gen small-caliber gun barrel

By Tyler Barth, U.S. Army

Army armament engineers at Picatinny Arsenal in New Jersey have been partnering with a pair of Pennsylvania companies -- one with alloy expertise and the other with forging metals -- to deliver a capable barrel for the Army's next generation of small arms.

Carpenter Technology developed the alloy and Geissele Automatics (also known as GWYNEDD) developed the production techniques for the barrels, while the U.S. Army Combat Capabilities Development Command (DEVCOM) Armaments Center provided the expertise in gun technology to deliver an innovation that is key to meeting the required capability.

A barrel made from GNB 200 mounted in an M240L, seen here in testing, is anticipated to be quintessential in the next generation of Army small arms. [Credit: U.S. Army photo]

 

 

This novel barrel design, created as part of two separate CRADAs (Cooperative Research and Development Agreements) between the Armaments Center, Geissele, and Carpenter, relies on the alloy called GNB 200, which provides Army small-caliber next-generation weapons with higher tensile strength and, with it, better wear resistance.

This advancement came after carefully reviewing the results of several projects that focused specifically on barrel technology over the past decade.

According to general engineer Daniel Cler, the design's principal investigator, DEVCOM had tested several "high alloy barrel materials" over the decade, seeking to help alleviate pressure buildup, corrosion, and mechanical wear, because next-generation weapons maintain significantly higher pressure than their legacy counterparts, which could, in turn, worsen barrel wear.

Additionally, for years, the U.S. Army has attempted to shift away from using hazardous heavy metals such as hexavalent chromium coatings, which is still renowned for its longevity but is known to cause significant health problems in production when hexavalent chromium is in solution.

Seeking to replace hexavelant chrome coatings with barrel materials that provide good wear and corrosion performance without coatings, the Army has performed research into a range of different metals. However, many of these materials were too hard to cold hammer forge, a method that is the current manufacturing technology for most military small arms. Because of this, the Armaments Center was refocusing on hammer forging and materials that were compatible with the process when it signed both CRADAs in 2022.

GNB 200 is, per Carpenter Technology's website, a "premium remelted alloy steel specially formulated for high-temperature wear resistance." According to Cler, GNB 200 is near the upper limit of what can reliably be cold-hammer forged.

The GNB 200 material made into an M240L configuration. [Credit: U.S. Army photo]

 

 

Carpenter Technology was already highly familiar with GNB 200, and as such provided samples for testing, along with several other materials. The Armaments Center gave guidance, processed information, provided support for analysis and result documentation, and carried out accelerated wear testing for proposed alloys.

Work with Geissele focused on manufacturability and feasibility. Geissele cold hammer forged the barrels themselves, provided input and direction for coating alternatives and specifications, performed testing on barrels, and processed parameters on manufacturability. In this stage, the Armaments Center gave its expertise on barrel technologies, provided ammunition for testing, and performed project oversight.

The parties involved tested the barrels in M240L machine guns over the project's third and final year, which ended in spring 2025. The material showed much better performance than the standard M240L barrel.

GNB 200 continues to inform the next generation of Army small-caliber weapons. Though the CRADA with Carpenter Technology has expired, DEVCOM renewed its CRADA with Geissele for another three years to continue development of barrel coatings.

The GNB 200 hammer-forged barrel is not the only project made in collaboration with Geissele. The pair also collaborated on developing a new rifle profile that has been shown to further reduce wear and improve dispersion. This profile received United States Patent 12,203,716 B2 on Jan. 21, 2025.

Cler said he was most proud of seeing a project he worked on has informed next-generation systems. He also noted how important it is to have some influence upon the industry in the correct direction, though he lamented not being able to get involved earlier.

"CRADA's are a good way to influence industry, so that as systems are developed to meet Army requirements, industry is ready to jump in with better solutions that are more aligned with the Army," he said.

Designfax Editor's Note: According to Carpenter Technology: "GNB200 is a premium melted alloy steel specially formulated for applications requiring high mechanical strength combined with very high toughness at -40°F. The clean microstructure produced by ARC/AOD melting followed by Vacuum ARC refining allows for the development of very tough properties. The high tempering temperature makes GNB200 suitable for applications that see temperatures up to 1000°F. The toughness at -40°F makes GNB200 suitable for applications in very cold environments."

Published April 2026

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