The Brutus 155mm self-propelled mobile artillery system is jointly developed by the companies AM General and the Mandus Group. The artillery mounts the same cannon as the M777 to a hydro-pneumatic, soft Recoil system for mounting on 6×6 modified chassis of M1083 five-ton FMTV (Family of Medium Tactical Vehicles truck). The Brutus 155mm Mobile Weapon System is an innovative system that re-purposes existing cannons, fire control equipment, basic issue items, and vehicles to deliver enhanced firing capabilities, mobility, and reduced crew vulnerability. The Mobile Artillery System utilizes and converts existing fielded towed howitzers and their prime movers into self-propelled howitzer weapon systems capable of rapidly emplacing, firing and displacing, thus creating a true “shoot and scoot” capability.

The Brutus incorporates a groundbreaking modular design. Due to its lightweight and smaller vehicle footprint it can be deployed by air, sea, truck and rail and is adaptable to multi-mission environments. It has been initially designed to use a 39 cal cannon and will be able to upgrade to a 52-58 cal cannon when available and is adaptable to international 155mm cannons of different caliber length. The hybrid soft recoil system greatly reduces the number of components compared to traditional towed cannon systems (250 vs. 2,500). The simplified design and operation reduces crew size, maintenance, and logistic support requirements. The Brutus truly meets the worldwide need for a light and inexpensive, truck-mounted, large caliber fire support weapon.

In February 2018, the U.S. Army announced it was again interested in exploring available options for a new mobile howitzer to replace its existing 105mm and 155mm towed types. The need soon appeared to develop a new 155mm system that would be available in both short- and long-barrel variants and come in a package better suit the demands of different types of Army artillery units. In November 2018, the U.S. Army has tested the truck-mounted artillery system, low-recoil 155mm howitzer Brutus at Fort Sill, Oklahoma. During the U.S. military exercise Northern Strike 2019, a Joint National Training Center accredited exercise, sponsored by the National Guard Bureau, the experimental Brutus 155mm self-propelled mobile gun was presented on July 25, 2019, on Camp Grayling, Michigan, United States.