The EX-41 Shoulder Fire Grenade Launcher was a prototype American pump-action grenade launcher designed and manufactured by NOS Louisville and Picatinny Arsenal with further development by Knight Armament Company in 1995. A design by NOS Louisville, the EX-41 was an attempt at combining the best traits from single-shot and automatic grenade launchers.
The EX-41 was designed in an attempt to develop a multiple shot grenade launcher, following in the veins of the China Lake and T148 grenade launchers; at that time, the standard grenade launchers in use were the M203 and Mk 19 grenade launchers. This project was headed by Naval Ordnance Station Louisville under a directive by the United States Marine Corps, with the goal of combining the traits of the Mk 19 and M203 into one package.
One prototype was built in 1995 by NOS Louisville and tested; this prototype was named the EX-41. The EX-41, while effective, was heavier than 7 kilograms (15 pounds) as specifications required and did not have the required effective range of 3,000 metres (3,300 yards; 1.9 miles). Improvements had to be made if the weapon was to be adopted; as such, NOS Louisville sent the sole EX-41 prototype to Knight Armament Company to add a flash suppressor and modify the design of the feed tube in November 1995. These improvements never came to be and the sole EX-41 prototype remains under KAC ownership.
The weapon was not well-liked by those who shot it, with KAC employee Trey Knight likening shooting the EX-41 to being "punched in the face".
The EX-41's form factor was quite similar to that of a shotgun, with a tube magazine located underneath the barrel. The weapon features iron sights, but also optics of an unknown make. The weapon also features a hydraulic buffer system.
The EX-41 uses specialized 40mm grenades developed by Indiana Ordnance. The grenades were a hybrid between low- and high-velocity grenades; this was intended to reduce recoil to an acceptable level but have the grenades retain a useful exiting velocity from the muzzle.
- The EX-41 is often confused with the China Lake grenade launcher; this was a separate project developed in the 1960s.