The M109 self-propelled Howitzer gun, known by IDF as "Rochev" (Rider), entered the Artillery forces' service before the Yom Kippur War (1973). In that war, only one battalion was equipped with these guns, the "Tiger" battalion. This battalion lost almost its entire B battery during the first days of the war. In the photos taken that time you can see the very first model, M109, with the shorter barrel, without the turret baskets and with a travel lock based in the center cover of the engine.

After Yom Kippur War (1973) war the IDF continued to equip the artillery battalions with the M109A1, so during the Peace For Galilee(1982). most the active-service battalions (non reserve units) except two operated the M109 (the other two operated M107 Romach self propelled guns). During the mid-1980's the IDF received the M109A2 model. In 1988 there was only one battalion not equipped with the Rochev.

The upgraded model, Doher (galloper) was introduced to the artillery forces personnel in 1993, Doher is improved Rochev. The IDF maintenance units designed it. This model was the last one on a row of designs, none of which made it to serial production. From this year, till 1997, all of the active service Rochevs were replaced by the Doher. After the active service units received their share, the IDF began to replace some of the reserve units' vehicles. Today one can find in the reserve units both the Doher & Rochev.

Two models of Rochev served with the artillery forces, A1 & A2, both differ one from another in some minor details. Both, as well, can be upgraded to Doher, the A5 model.

The M109A1 featured a new longer barrel, and various other improvements, with a maximum range of 18,100m. The M109 was the first model, with a very short barrel, double baffle muzzle brake, large fume extractor, and a maximum range of 14,600m.

The M109A2 is a new production weapon which incorporated 27 mid-life improvements to the M109A1. The improvements provide for increased Reliability, Availability, and Maintainability (RAM) and safety characteristics as well as enhanced operational capabilities.

Major changes from the M109A1 include a redesigned rammer and improved recoil mechanism, engine operation warning devices, a redesigned hatch and door latches, an improved hydraulic system and a bustle designed to carry an additional 22 rounds of ammunition.

The M109A2 has the long tube M185 cannon installed in the M178 gun mount. The cab has a rear bustle rack which provides an increased ammunition stowage capacity. It has an all weather ballistic shield mounted over the panoramic telescope; counterbalanced travel lock and provisions for mounting the M140 alignment device.

The M109A2 entered production at BMY Combat Systems in 1978, with first deliveries made early in 1979. The first production quantity of 103 vehicles was with FY77 funding. M109A2 pro 36 M109A2s were produced for the National Guard using FY82 funds.

The differences between the A1 & A2 models are mainly internal, for example the shells' loading system.

Three external differences can be spotted:

1. In the A1 model, the sight is covered with armored "cup", held by single bar. The "cup" can be found either in a closed (down) position or opened (up) position. The A2 model has ballistic shield, surrounding the sight, with a transparent window in one of its sides. The shield can be turned 360 degrees. The crewmen call this shield "The television".

2. Most of the A1 type vehicles have the old type of the barrel speedometer, mounted on the inner-upper side of the barrel. This old type is a rectangle, with a cone in its front. Most of the A2 type vehicles carry the advanced type, which is a rectangle without the cone (instead, it has a round pale yellow window in its front side.

3. In A1 models, mainly those that served for training purposes, one can spot a device in the upper side of the barrel, to carry the 0.5" SMG. This SMG was used for direct-line-of-sight training. This device is not found in neither the A2 model, or in A5 model.