Back in 2011, the United States and China both introduced electronic fire control systems for 40mm long-barrel grenade launchers. Nearly a decade later, both of these longer range, highly accurate 40mm weapons are still in production. Both are niche weapons and popular enough to keep getting made and upgraded.
The Chinese LG5 is a 13 kg (28 pound) semi-automatic weapon that is 1.23 meters (49 inches) long and uses a drum magazine holding up to 50 rounds. The LG5 is available in different versions for 40x53mm NATO or Chinese grenades as well as 35x32mm grenades for the Chinese army version of the weapon (the QLU-11). Both versions use the same type of computerized fire control system that enables accurate fire out to 2,000 meters. At shorter ranges, usually about 600 meters, the LG5 can put grenades through a window or doorway. The LG5 can also use fire an airburst grenade to hit targets behind an obstacle. China described the LG5 as a “sniper” weapon and it certainly was a 40/35mm grenade launcher capable of unusual accuracy for such weapons.
The American Mk 19 was developed by the U.S. Navy in the 1970s for use on river and coastal patrol boats. The Mk19 didn’t see much combat until the 1991 Gulf War when the army and marines recognized it as a very effective weapon in open land areas, not just open water. From the beginning, the Mk19 was quite effective with the usual “iron sights” found on rifles for over a century. But users noted the electronic sights becoming available for rifles and machine-guns in the late 1990s. Eventually, in 2011, an electronic sight was developed that worked with the Mk 19, producing a very accurate long-barrel 40mm automatic grenade launcher. This electronic sight, combining a GPS, laser rangefinder and computer, was called the Mk19 FCS (Fire Control System). The FCS enabled gunners to put the first round on the target, at extreme ranges; over 2,000 meters. The FCS can also fire an accurate pattern of 40mm grenades at those same ranges. Moreover, the GPS enables an FCS equipped Mk19 to accurately fire on a target the gunner can't see. The FCS also has a camera, which can mark targets, out to 5,000 meters, on a photo, which can be then transmitted to other troops or headquarters. The FCS is also very easy to use for anyone with Mk19 experience. You laze the target to obtain range, and then use the aiming dot in the sight to mark where the rounds will go.
Getting the first rounds on the target is very important because once those 40mm rounds start going off, the enemy will dive for cover. With the older sights, the first round was a guess by the gunner, and usually close, but not on the target. Subsequent rounds were on target, but by then many of the enemy troops were behind cover.
The FCS was but one of many improvements. Mk19 gunners loved the new sight and the word has quickly gotten around. This created so much demand that the army had problems getting FCS, which were still technically in development in 2011, to all the troops who were demanding it.
While the FCS was still in development, work began on a new lighter and more effective Mk47 model grenade launcher that had an even more capable integrated FCS. The Mk47 was available in 2009 but it was not innovative enough to replace the MK19. For users, the Mk19 gut the job done and was cheaper and the troops liked it and knew what it could do in combat. The Mk19 was improved with a new recoil system that kept the weapon steadier when firing. This improved accuracy, especially when the Mk19 was used from a moving vehicle.
The Mk47 is lighter (18.2 kg/40 pounds) than the 35 kg (77 pound) Mk19. It is a little more compact and has the electronic sighting and arming system which enables the gunner to determine the distance of the target (with a laser range finder), then push a button to have the weapon electronically program each shell, just before it is fired, for the number of seconds until the shell will explode, at the proper range from the gun, and above the enemy troops. If the time fuze does not work, the shell explodes when it hits something. The Mk47 can also operate like the Mk19, using "dumb" ammo that lacks the time fuze. This is what the new FCS does for the Mk19.
Both these 40mm weapons have a max range of 2,000 meters and an effective range of about 1,500 meters. The Mk19 weapon, with a tripod, weighs 61.8 kg (136 pounds), while each 48 round magazine weighs 27.3 kg (60 pounds). There is a new, lighter, tripod available, that reduces weight by 13.2 kg (29 pounds) The Mk19 effective rate of fire is about one round per second and is usually fired in short (a few rounds) bursts of these 542 gram (19 ounce) grenades. These individual 40mm grenades can kill or incapacitate most people within six meters of the explosion and can wound at twice that.
The Mk19 is more complex than your usual machine-gun, expensive (about $20,000 each) and jams more frequently (once every thousand rounds, compared to once every 10,000 rounds for the M2 12.7mm machine-gun.). But it is reliable enough to remain popular and in demand. The lighter Mk47 costs about 50 percent more and is about as reliable as the Mk19.
The LG5 is semi-automatic and finally got some combat experience in Yemen, where Saudi forces began using it in 2018. The Saudi troops were satisfied and more LG5s were ordered.