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Land ForcesUnited States

M109A1

155mm self-propelled howitzerFielded 1970Pending verification
Land ForcesUSA
Identification silhouette. Not drawn to scale between entries.
Fact cardConfidence · Source
System
Type155mm self-propelled howitzer
Date of introduction1970
ProliferationAt least 12 countries
Crew6Med[1]
Dimensions and weight
Width3.15 m10 ftMed[1]
Height3.28 m11 ftMed[1]
Weight24.07 tMed[1]
Automotive performance
ChassisThe M108 and M109 shared a common chassis (along with the M113 APC), but the M109 was heavier and had a larger gunMed[1]
EngineDetroit Diesel 8V71T DieselMed[1]
Engine power450 hpMed[1]
Cruising range390 km242 mi · 211 nmiMed[1]
Max road speed65 km/h40 mph · 35 ktMed[1]
Fording depth1.07 mMed[1]
Protection
Hull ArmorThe M109’s protection consists of up to 32 millimeters of armor, which is only effective against small arms and grenade/artillery fragments.Med[1]
NBC Protectionnone fittedMed[1]
Armament
Elevation-3/+75 deg (-53/+1,333 mils)Med[1]
Rate of fire (max)4 rpmMed[1]
Rate of fire (sustained)2 rpmMed[1]
Main armamentM185 155 mm/L39 howitzer, 155 mmMed[1]
Secondary armamentM2 BrowningMed[1]
Maximum firing range14.6 km9 mi · 8 nmiMed[1]
Fire control
Main Gun StabilizationYesMed[1]
Variants
M109First produced in 1963. It had a 23 caliber 155 mm M126 gun in an M127 Howitzer Mount and carried 28 rounds of 155 mm ammunition. It was also armed with a .50cal M2HB machine gun with 500 rounds of ammunition. Easily ide[1]
M109A1Replaced the M126 gun with a longer barreled, 39 caliber M185 gun, increasing the maximum range to 18,100 meters.[1]
M109A2Incorporated 27 Reliability, Availability, and Maintainability (RAM) mid-life improvements. Most notably, the long-barreled 155 mm M185 cannon in the new M178 gun mount, ballistic protection for the panoramic telescope, [1]
M109A3 and M109A3BM109A1s and M109A1Bs were rebuilt to M109A2 standard respectively. Some A3s feature three contact arm assemblies, while all A2s have five.[1]
M109A4M109A2s and M109A3s improved with Nuclear, Biological, and Chemical / Reliability, Availability, and Maintainability (NBC/RAM) improvements, including air purifiers, heaters, and Mission Oriented Protective Posture (MOPP[1]
M109A5Replaces the 155 mm M185 cannon in an M178 mount with a 39-caliber 155 mm M284 cannon in an M182 mount, giving the A5 a maximum range of 22,000 meters with unassisted projectiles and 30,000 meters with Rocket Assisted Pr[1]
Weapons and payload options · 3Confidence · Source
Copperhead155 mm ammunition
Med[1]
Quantity
28 Rounds Total of any Combination Projectiles
DPICM155 mm ammunition
Med[1]
Quantity
28 Rounds Total of any Combination Projectiles
RAAMS Long155 mm ammunition
Med[1]
Quantity
28 Rounds Total of any Combination Projectiles
Summary

The M109A1 variant features an improved gun—the M185 155 mm/L39 howitzer. This artillery system was introduced in 1970 and deliveries commenced in 1973.

Draft entry. Values come from the cited public sources and are awaiting editor verification.
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Operators
United StatesUnited Arab EmiratesSwitzerlandDjiboutiEthiopiaGreeceIranKuwaitMoroccoOmanPeruThailand
Sources
  1. M109A1 American 155mm Self-Propelled Howitzer (SPH), U.S. Army TRADOC G-2 Worldwide Equipment Guide (ODIN)
    Published/updated 2026-03-20 · Tier 1 · checked 2026-10-10
Change log
  • 2026-10-10 Entry created from the Worldwide Equipment Guide (ODIN), bulk import