Doher (galloper) was introduced to the artillery forces personnel in 1993, Doher is improved Rochev (M109A1 and M109A2). 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.
Differences Rochev & Doher
All types share the same hull, turret, barrel, engine & transmission. Most of the improvements of the Doher are internal and can't be seen from the outside: Inertial Navigating System (INS), air filtering system, and some changes in the driver's panel & cabin and NBC protection added. The external, visual differences are:

1. Two sub machine guns on the Doher's turret, only one in the Rochev. The additional SMG is
      positioned near the sight ballistic shield. 
2. Electrical travel lock (known in Hebrew as "BiFoot") in the Rochev one of the crewmen has to lock
      manually the barrel, most of the time the driver, with the assistance of the sight operator. In the
      Doher the crewmen can do it automatically, by electrical operation. The Doher's travel lock is
      thicker than the Rochev's, and has a rectangle box in its front side.
3. External Generator the Doher is equipped with external Generator, positioned instead the right-back
      basket and its two external cells. Due to the lack of one basket, the left basket is a bit bigger (to
      contain the camouflage cover).
4. Different shape of the commander's turret the Doher's NCO turret can be locked in slit position, a
      position that does not exist in the Rochev.
5. Different Tactical markings the upgraded capabilities of the Doher changed in some manners the
      way the artillery battery is operated. Due to this fact, beside the different kind of V's and numbers,
      one can find also a Hebrew letter (Aleph, Beit, Gimel) markings.

Most of this information provided by Amir Segev.
Enter into service
Ammunition storage
(+ 80 on alfa truck)
Fire Range
22 km
Fire Rate
4 rds/min for 3 min
1 rd/min for 60 min
Road range
350 km
28.2 tons 
50 kph