Army and Marine Corps M198 Howitzer

Marine Corps and Army users of the M198 155-millimeter towed howitzer want to replace the 15,600-pound cannon with a light -weight weapon to ease the burden on crews and to improve air and ground mobility. The Marines have found it hard to tow the M198 over soft terrain, and only their heavy-lift helicopter can move the weapon by air. This report discusses whether the Marine Corps' and Army's reported maintenance problems with the M198 justify accelerating the development of a replacement weapon. GAO also provides information on the Marine Corps' and the Army's planned development of a new, light-weight 155-mm howitzer.

GAO found that: (1) by themselves, the maintenance problems with the M198 howitzer do not justify accelerating the development of a replacement; (2) although Army and Marine Corps users of the M198 have experienced recurring maintenance problems with the howitzer, some of these problems have been resolved, and solutions to most of the remaining problems have been identified but not funded; (3) even with these problems, availability of the M198 reported by Army and Marine Corps units over the last 6 years averaged about 93 percent and 89 percent respectively; (4) the Marine Corps believes that the poor mobility of the M198 is a more important reason than maintenance for replacing it with a lighter-weight weapon; (5) however, the anticipated air mobility improvements are dependent on the ability of the MV-22 medium-lift aircraft, now in engineering and manufacturing development, to lift a 9,000-pound howitzer; (6) so far, the developmental aircraft has not shown that it can lift that weight; (7) current light-weight howitzer candidates will fire projectiles to 30 kilometers, the same range as the M198; (8) to achieve the objective firing range of 40 kilometers, the weight of the new howitzer would have to be increased, but an increase in weight could negate mobility improvements; (9) a new munition, the XM982, currently being developed by the Army independent of the light-weight howitzer development program and scheduled to become available in fiscal year 1998, is expected to achieve the desired 40-kilometer range; and (10) however, it has not yet been tested in the competing light-weight howitzer prototypes.