Since the early sixties, the US Army has been operating 155 mm M109 self-propelled howitzers. Over the years, this technique has been repeatedly updated and improved. For example, a massive modernization of self-propelled guns under the M109A7 project is underway right now. In addition, there were attempts to create fundamentally new ACS to replace the outdated M109. However, none of them has yet led to the desired results.
M109 to M109A7
The M109 self-propelled guns of the first version entered service in 1963. In the early seventies, its first modernization was carried out, as a result of which the M109A1 armored vehicle with an improved chassis and armament appeared. The next projects with the letters "A2", "A3" and "A4" involved the improvement of various systems and the installation of new tools. Also, on their basis, modifications of the ACS were created for some foreign customers.
The M109A5 self-propelled gun received the M284 gun with a barrel length of 39 calibers, which increased the firing range. In the early nineties, the M109A6 Paladin ACS was developed on the basis of the "A5". While maintaining the bulk of the units and devices, such a self-propelled gun received new fire control means, communication systems, etc. All this led to an increase in the survivability and effectiveness of fire.
The current version of the self-propelled gun is the M109A7, which has now been put into series. Such an ACS differs from previous vehicles in an improved chassis, enhanced protection and a modern FCS. The gun remains the same, but is supplemented with automatic loading. The M109A7 features improved technical, operational and combat characteristics.
It should be noted that the M109A7 project was developed after the termination of work on two fundamentally new self-propelled guns. Having received no new machines, the Pentagon decided to continue the development of the existing one.
"Crusader" instead of "Paladin"
The first attempt to replace the M109 with a newer 155mm self-propelled howitzer was made in the early nineties. The development of the concept of such a sample was carried out within the framework of the AFAS (Advanced Field Artillery System) program. Subsequently, in 1994 it was renamed Crusader. Experienced self-propelled gun bore the designation XM2001.
The Crusader project was based on some interesting and unusual ideas. The ACS was proposed to be built on a new chassis with a gas turbine engine. The armament was serviced only by automatic equipment. To obtain maximum combat characteristics, a promising XM297E2 rifled gun with a cooling system was proposed. Fire control was carried out using a digital system with all the necessary components.
At the beginning of 2000, an experienced self-propelled gun XM2001 Crusader entered the training ground. An experimental transport-loading vehicle was also built. For two years, prototypes have been tested and demonstrated their capabilities. The self-propelled gun has confirmed the high range and accuracy of fire in different modes of fire. More than 4 thousand shots were fired at different ranges using all compatible projectiles. The performance characteristics of the ACS corresponded to the calculated ones.
According to the plans of that time, the serial M2001 self-propelled guns were supposed to begin service in 2008. However, already in 2002, the Pentagon analyzed the current results of the Crusader program and came to negative conclusions. The command considered that the proposed ACS, having some advantages over combat equipment, turns out to be too expensive for procurement and operation. The cost of a serial combat vehicle was approaching $ 25 million. Any other existing or promising model was many times cheaper.
The total cost of the Crusader program reached $ 11 billion. Despite the serious expenses, they decided to abandon its continuation. The army did not receive a new self-propelled gun, and the "Paladin" remained the basis of self-propelled artillery.
FCS MGV program
The next attempt to create a new self-propelled gun was made as part of the infamous Future Combat Systems (FCS) program. The program provided for the development of a large number of new types of equipment for various purposes, suitable for putting into service in the foreseeable future. In 2009, FCS was stopped due to the lack of real prospects. The closure of the program led to the abandonment of several new technology projects, incl. 155 mm self-propelled howitzer.
The XM1203 NLOS Cannon ACS was to become one of the representatives of the new family of vehicles. It was proposed to build a medium-weight airborne self-propelled gun with a 155 mm gun. To speed up development and maximize performance, it was planned to widely use developments on the Crusader theme. The resulting sample was to be equipped with various automation and receive a modern OMS.
In 2008, BAE Systems completed the development of the XM1203 and built the first prototype. Over the course of several months after that, several more of these machines came out of the assembly shop. In total, eight prototype self-propelled guns were involved in the tests.
During test firing, the XM1203 confirmed the ability to use various 155-mm projectiles and showed high reliability of automatic loading and fire control. The main characteristics corresponded to those declared, but the refinement and improvement of the design were required. In the medium term, the self-propelled guns could enter service.
However, in 2009, the NLOS Cannon project was closed along with the entire FCS program. The general program for creating technology turned out to be too complicated and expensive. The development of a promising ACS was also not distinguished by simplicity and low cost. As a result, it was decided to stop the design of all new samples.
Despite all the successes, the XM1203 self-propelled gun was also cut. Unnecessary prototypes were sent for storage and disassembly. The place of the main ACS of the US Army remained for the M109A6 Paladin indefinitely. Soon after the closure of the FCS program, an order appeared for the next upgrade of the M109. The result is the current M109A7 self-propelled howitzer.
ERCA project
Several years ago, the Pentagon launched a new Extended Range Cannon Artillery (ERCA) program, which should result in the emergence of new weapons with an increased range of fire. Several prototypes of this kind have already been built, incl. self-propelled howitzer XM1299. Like previous models, this ACS is seen as a promising replacement for the current M109A7.
ACS XM1299 is built on the basis of an updated tracked chassis, which has a separate compartment for the entire crew. The armament tower is uninhabited and equipped only with automatic equipment. A 155-mm howitzer is mounted in the turret, which is a modification of the experimental M777ER product. Such a gun has a barrel length of 58 calibers, which should provide a high muzzle velocity and increase the firing range. The howitzer is serviced by an automatic loader providing 10 rounds per minute.
The fire control system is built on modern components and takes into account current challenges. In particular, the coordinates of the firing position can be determined both using satellite navigation and using an inertial system - in case of jamming GPS signals. Data exchange with other ACS and command is provided.
For the XM1299, a new XM1113 active-reactive guided projectile with increased range and accuracy characteristics is being developed. With the use of such ammunition, the self-propelled guns will be able to conduct effective fire at ranges of more than 100 km. Such characteristics are planned to be obtained in the next few years. At the same time, during the tests, a firing range of 70 km was already shown.
Further work on the XM1299 will take several years. Serial production and deployment of new equipment in the troops will begin no earlier than the first half of the twenties. Whether it will be possible to fulfill such plans is unclear. Within the framework of the ERCA program, several critical problems have to be solved, and only after that real samples will be able to enter service. How successful further work will be - time will tell.
Awaiting replacement
Currently, the American industry is serially modernizing the existing self-propelled howitzers M109A6 according to the current project "A7". In the near future, this order will be fully executed, which will lead to a noticeable increase in the combat qualities of artillery. In addition, the result of the modernization will be the extension of the resource and service life of the equipment.
In parallel, a new ACS is being developed for the future replacement of existing armored vehicles. However, the XM1299 ERCA project is not the first of its kind. Attempts to replace the "Paladin" have been made since the early nineties, and so far none of them have been successful.
The first attempt in the form of the XM2001 Crusader project failed due to the excessive complexity and high cost of the equipment. The second was the XM1203 NLOS Cannon project, closed with the larger FCS program. This time, the reason for the refusal was the inconsistency of the main program with the current views and plans of the Pentagon. Now the industry is working on the XM1299 self-propelled guns and again shows technical successes. Whether it will be possible to realize the full potential of this project and bring it to a series is a big question.
However, the US military is not prone to pessimism and gives the new development the highest marks. Once again, statements are being made about high performance and a great future, as well as about the upcoming replacement of old armored vehicles. The near future will show how correct the current assessments are, and whether all plans will be fulfilled.
