The M777 "Ultra-lightweight Field Howitzer" (UFH) was developed as a private venture (under Vickers Shipbuilding and Engineering Ltd) and eventually evolved into a formal replacement for the aging series of M198 155mm artillery guns of the United States Army and Marine Corps (among other global users). The M198 itself began operational service in 1979 and holds design origins dating back to the late 1960s. Some 1,600 units were ultimately produced and these have gone on to see widespread combat service around the world. BAe Systems was awarded a new defense contract to develop and produce the M198's replacement, which became the "XM777". The production form series then took on the name of "M777". The M777 has already see combat actions in Afghanistan with US forces and entered service in 2005. Beyond its use by the United States military, the M777 has also been adopted by the Australian and the Canadian armies which operate 35 and 37 gun systems respectively (as of this writing - 2012). The US Army and USMC maintain some 580 guns another possible 421 on order (2012).
The M777 system weights less than 10,000lbs which makes it the lightest gun in its particular classification - lighter than that of the preceding M198 series. This sort of engineering prowess makes the M777 system extremely adaptable in-the-field and transportable through a variety of means improving upon the original M198 in both its tactical and logistical qualities. The M777 can therefore be transported by land via approved service truck or through the air by approved aircraft. For the latter, this includes the new MV-22 "Osprey" twin-rotor series helicopters as well as the tried and true CH-47 "Chinook" tandem-rotor transport helicopters to which the M777 unit is hung underneath the airframe. For fully-enclosed air transport, the M777 can be fitted into the hold of the C-5 Galaxy, C-160 Transall, C-141 Starlifter and C-130 Hercules series of medium-to-large transports.
The M777 gun and gun mount sit atop a carriage system made up of a split trail, two-wheeled configuration (consisting of the body and saddle). When setup to fire, the M777 adopts a four-point stance for maximum support and to help content with the weapon's inherently violent recoil. The muzzle is capped by a large double-baffled muzzle brake for this purpose as well. Elevation and traverse are handled at the rear of the weapon near the breech as is loading and reloading. The M777 is crewed by five specially-trained personnel to handle the various functions of the gun (the M198 required 9 personnel). The barrel is 155mm (39 calibers) and weighs in at approximately 9,300 lbs (unlike the 15,700lb weight of the M198 series). The weapon achieves a rate-of-fire of up to five rounds per minute with a sustained rate of two rounds-per-minute. The barrel is designed for a lifespan of 2,650 firings. Rocket Assisted Projectiles (RAP) increase the effective range of the weapon system out to 18.6 miles (30km). The base range using conventional projectiles is 15 miles. Use of titanium across the M777's design lowers overall operating weights.
The M777A1 standard (previously designated as the M777E1) features a custom-designed digital firing system that uses the latest in positioning and targeting technology. The M777A1 has already begun replacing the current generation of M198 howitzers in the US Army and US Marines inventory. Another variant, the M777A2, has already seen combat action since January 2008. It is based on the M777A1 but slightly revised to fire the new Raytheon Excalibur precision projectile (with its 25 mile range limit) with a new software update. The US National Guard is also an active user of the M777 series. The A2 mark is currently the latest production standard of the M777 family.
While the weapon is British in its true origins, final assembly of the guns takes place in the United States out of the BAe plant at Hattiesburg, Mississippi. Roughly 70% of the weapon is completed in the United States.
2016 - A vehicle-mounted version of the M777 was unveiled in 2006 and is known as the M777 "Portee".
April 2016 - It was revealed that tests were underway for M777ER (Extended Range) variant. This model adds a 6-foot barrel extension to the existing M777 barrel, increasing range out to 70 kilometers - more than doubling the range of the weapon. The gun has been demonstrated to USMC elements at the Yuma Proving Ground (Arizona).
January 2017 - The Canadian Army undertook successful live-fire testing with M777 howtizers involving an anti-jamming device for its GPS units.
November 2018 - The Indian Army has formally introduced its new stock of M777A2 series 155mm towed field guns from the Untied States. One-hundred forty-five of the guns will eventually make up the Indian stock, spanning some seven regiments.