The M109 Series Howitzer


(The M109A6 Paladin)

Early Stages

The M109 series howitzer is a self propelled, tracked, artillery piece designed to add flexibility, mobility, and power to mechanized armor brigades. It uses a 155mm projectile, allowing for explosive power while maintaining a long range at minimal propellant. The M109 has gone through many phases since its initial design was fielded in 1963. The current version, the M109A6, is the principal self proppelled artillery piece of the United States Army.

The M109 was designed by BAE Systems Land and Armaments in the early 1960's. The design was born of a need to replace the M44 howtizer. The system was originally designed to be either a 105mm or 156mm projectile, however late in design, the decision was made to stay with the 155mm projectile. Then in June 1963 the first M109 howitzers were shipped out to be fielded.


(The M109 Howitzer)

Original Design

The M109's initial design provided a weapon of unmatched caliber. It provided a speed and mobility that had been unseen up to this point in warfare. The system brought an ease to direct and indirect fire, due to a more sophisticated digital setup. The M109 used a M126 tube to deliver indirect fire up to a maximum range of 14,500 meters. The system was also able to carry 28 rounds of ammunition all of which was loadable internally.

A1 and A2

The M109A1 saw some small changes to include the addition of the M126A1 howitzer tube, which expanded the range somewhat. It wasn't until the A2 model was fielded that the M109 howitzer began to see serious upgrades. The A2 received a M185 howitzer tube, which expanded the range to 23,500 meters, an impressive range at the time. More protection was em-placed for the crew, as well as the addition of the travel lock. The travel lock held the howitzer tube in place while the howitzer was moving. This feature kept the tube from taking damage while the howitzer was moving through rough terrain. Ammunition storage was also increased from 28 to 36 155mm rounds.

A4 and A5

The A4 model was the next model to see many upgrades. MOPP gear and NBC/RAM (nuclear, biological, chemical/reliability, availability, maintainability) were improved with air purifiers and heaters. Perhaps the greatest upgrade seen in the A4 model was the switch from electronic tube traversing to hydraulic tube traversing. The hydraulic system was much less prone to failure and featured an over ride system in case all electronics in the howitzer went down. This allows the Chief of Section to manually aim the tube in case of emergencies. The A5 model saw a new howitzer tube, the M284. This tube allowed for a max range of 23,500 meters, but also enable the howitzer to fire RAP (rocket assisted projectile) rounds a total of 30,000 meters. The A5 was also enabled to carry 36 rounds of 155mm ammunition.


The M109A6 “Paladin” is the current system used by the U.S. Army. While there are many variations used by different NATO nations, this is the most commonly fielded version. The Paladin utilizes newer fully digital systems that allow for unprecedented accuracy and exceptionally expedient firing. Upgrades to communications equipment also allow for a stronger resistance to electronic warfare. The Paladin, however, is the first true self propelled artillery piece. It's only requirement for firing is to come to a stop. Previous models required the howitzer come to a stop and “emplace”, a process where the howitzer must be laid and called “safe”. Emplacement took several minutes and this was under the best of circumstances by highly trained crews. The removal of emplacement allows the Paladin to fire on a target within 30 seconds of stopping. This capability also negates enemy counterfire batteries, the most dangerous aspect of artillery.

(The following is based on opinion, you have been warned)

The M109A6 has had a strong impact on modern day standard warfare. As evidenced by the first Gulf War and the beginning of the second Gulf War, the Paladin's ability to fire quickly and move to a new position gives it an edge over standard, towed artillery pieces. This mobility combined with modernized propellants and RAP rounds give the Paladin a lethality that few weapons can match. The doctrine related to the weapon has proven effective, time and time again.


There is a M109A7 model howitzer that has been made and field tested. There have been talks of contracts and purchasing of this model, however it is the opinion of me, the writer that it's malarkey. The M109A7 shows few improvements over the M109A6, at least nothing that justifies the heavy price tag behind the weapon. Essentially, the weapon will become more integrated digitally than the A6 model. However, this doesn't attend to the issues that the Paladin have encountered in the modern battlefield.

Problems with the Paladin

The main issue has been simple. The need for an auto loading feature has proven itself evident time and again. While the Paladin is able to “shoot and scoot”, fire and then exfill the area in a timely manner, I believe at least a portion of its success in the Gulf Wars were due to Iraqi inability to gather proper intelligence. What I mean by this is simply that they lacked the radar capabilities to properly detect American artillery and engage them in counterfire. While many have noted that the Paladin is lacking in range, I believe this is a non point. The evolution of the modular artillery charge system (MACS) as well as the development of the Excalibur GPS guided round were great cost saving measures that enabled the Paladin to stay in continuous use well past the end of it's projected life cycle. Many have used my first point, the need for auto loading feature, to push for a replacement of the entire system. The Crusader was the initial response.

XM2001 Crusader


(The XM2001 Crusader)

The Crusader boasts a more powerful engine, allowing for a higher max speed and greater movement over rough terrain. It's auto loading feature allowed for roughly double the firing speed of the same projectile, while simultaneously allowing for about a 30% increase in range. This is possible due to the removal of the gun crew and using that space to augment the weapon. The Crusader would only require a driver. It would also remove the need for a “Fire Direction Center” (FDC). This is possible by having a fully integrated safety data computation system. The FDC would normally provide these safety computations.

The major issue I have with this system is that it takes all of the human elements out of the strategy. I don't know that this is a good idea at this juncture. While I will not go to far down this philosophical hole, I think that we as a society are already to disconnected from the realities of war and this would simply make that worse. There is also the question of the price. The Crusader, while not having an official price tag, was projected to cost much, much more than the Paladin system. It is my belief that the M109A7 should simply incorporate an auto loading feature, with perhaps a small chassis overhaul. This would alleviate cost concerns while continuing the modernization of the self propelled artillery world.


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