The M777’s lightweight construction isn’t just valuable for air transport

Thursday, June 8th, 2023

In 1979, the M198 155mm medium-towed howitzer entered service:

At just over 36 feet long and weighing in at approximately 16,000 pounds, the M198 could rain high-explosive hell down on targets from 14 miles out, cycling and firing 95-pound M107 shells with a 9 or 10-person crew.

By the 1990s, the U.S. was shopping for a new, lighter artillery platform:

The answer came in the form of an artillery system that had been in development in the UK since the 1980s, initially under the banner of Vickers Shipbuilding and Engineering (later purchased by BAE systems). At 35 feet long, with a 16.7-foot barrel, this new artillery platform was just slightly shorter than the M198 and fired the same 155mm rounds… But thanks to the widespread use of titanium and aluminum alloys in its construction, weighed 40% less than the M198, at just 9,300 pounds.

The new M777 was so light, in fact, that it could be slung beneath helicopters or delivered via all sorts of cargo aircraft. While it would take two C-130s to deliver an M198 artillery system to the battlefield, the entire M777 setup could arrive in just one.

But the M777’s lightweight construction isn’t just valuable for air transport. In combat, where artillery crews regularly “shoot and scoot” (fire off a number of rounds and then relocate before you can be targetted), the M777’s light weight makes it easier to quickly break down and move. In fact, well-trained crews can break the M777 down for transport in just about three minutes and set it back up again in about the same. While traveling, its light weight means M777s can be towed through muddy roads and across wet fields that would hinder the progress (or completely stop) heavier weapon systems.

The M777 also received improved high explosive shells — the 103-pound M795, which carries 24 pounds of TNT and offers a kill radius of a whopping 70 meters. Each M795 carries the destructive firepower of a Hellfire missile, but delivered at just a fraction of the cost.

Crews can fire five of these massive rounds per minute, reaching targets 19 miles away. Newer (and more expensive) GPS-guided rounds with deployable stabilizing fins known as the M982 Excalibur can reach even further — as far as 25 miles out.

The M777 may have been made out of some of the same materials as the SR-71, but Uncle Sam continued to trick its new howitzer out even after it entered service in 2005. Throughout the 2010s, America’s M777s all received full-bore chrome-plated barrel tubes said to extend their service lifespans by as much as 300%.

In 2017, the efficacy of this upgrade was proven in battle, when a single Marine M777 battery fired more than 35,000 rounds at ISIS targets in Syria over just five months. That’s more than all of the 155mm artillery rounds fired by the entire U.S. military in the 2003 invasion of Iraq. But despite this incredible volume of fire, the Marines only burned through two of these new chrome-plated barrels in the process.

Other upgrades include the addition of precision-guided fuse kits in 2016 that reduced the margin for error in targeting high-explosive rounds by a whopping 85%, bringing accuracy from a 200-meter margin to under 30 meters. With a 70-meter blast radius, that jump in accuracy effectively ensures a direct hit when M777 crews have good targeting data.


American M777 crews now use a digital fire-control system operated via a tablet computer that allows them to rapidly identify targets and engage them without having to do any of the math. This not only speeds up the firing process, but also eliminates user error caused by battlefield stress or exhaustion.


For situations that call for even greater accuracy, however, the M777 can rely on target data relayed to it by the Army’s Joint Effects Targeting System, or JETS. These one-person-portable targeting systems are carried into the field by forward observers and Joint Terminal Attack Controllers who identify targets at ranges as far from the user as 2.5 kilometers.


  1. Gavin Longmuir says:

    Interesting! There have been contrary reports from the Ukraine that the M777 has been disappointing in actual use against a peer opponent. The light weight of the gun means that it tends to get bent when towed in frequent moves over rough territory — a problem which the US avoids by mainly moving the gun by helicopter lift. Of course, helicopter lifts become impractical against a peer opponent.

    But the big smile is reducing the weight of the gun by using titanium — imported from Russia! That sounds sustainable in the kind of aggression our Political Class so desperately wants.

  2. Pseudo-Chrysostom says:

    It is also distressingly prone to just exploding and killing all the crew when you try to fire it. Doubtlessly the Poindexter’s and McNamara’s on the design committee (and you better believe it’s all designed by committee) thought it was a great idea to shave a few extra pounds off by literally shaving off from the breech as well. The radio electronics it uses to communicate with other units in the battery were also easily trackable by the Russian forces, so use of them in the field often resulted in quickly coming under countery-battery fire, sometimes even before they actually opened fire.

    It’s a trend and you see much the same kind of problems with other GAE equipment as well, such as the Javelin. They were so finicky and prone to being damaged by the slightest rough treatment (things being banged, dropped, and bumped into while in a rush is an inevitability) that very few were actually operational when they needed to be used, and those that did technically manage to fire off very rarely resulted in a telling effect. In fact it’s not certain if there is even a single case where a javelin actually successfully knocked out a tank; in a war where everything is being recorded on video, cases where you cannot find any video examples at all is notable.

    The conflict is full of examples like this. The preaching class spends a month talking about a different NATO wunderwaffe that will Turn The Tide In This War, then quietly forget about it once banal operational realities sour expectations, then it’s on to the next one to keep the goldfish perpetually distracted. Happened with Javelins, happened with Bayraktars, M777s, JDAMs, Patriot, and soon we will add Leopards and Challengers to the list too.

    You know that one program on that one operating system by that one company? That is full of ‘features’ that make things more difficult and doesn’t let you do what you actually want to do? I’m sure everyone who has used computers in the last 20 years has had the pleasure of this experience at least once.

    Well imagine that same clade of people, except they are selling you weapons to fight in a war instead.

  3. Pseudo-Chrysostom says:

    Tangentially, the main problem with using aluminum as a structural material is that, unlike steels, its fatigue limit is effectively zero. That is to say, even slight loads and cycling will cause microstructure deformations that weaken the material and eventually cause failure. That is why aeroplane fuselages, for example, many of which tend to be primarily composed of aluminum alloys, have strict time limits on their lifecycles, even on light duty.

  4. Bob Sykes says:

    If you’ve ever seen film of it firing, the gun jumps all over the place. Its weight is completely overcome by the impulse of the 155 mm shell. The gun has to be completely reaimed after every round, and the extreme recoil requires frequent maintenance and repair.

    This was fine against militias with no artillery, but not against a full peer with superior artillery.

  5. McChuck says:

    The M198 has a longer range with the same shells, and was always more accurate. But if you really want longer range and greater accuracy, we need to bring back the old 8″ (203mm) guns.

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