By the end of the Korea War (1950-1953), the American Army was in need of modernization to replace many of its weapon systems that dated back to World War 2. One need ultimately became air-portable, tracked artillery systems that could be transported over distances to the awaiting army units. A requirement put forth by the US Army became a self-propelled artillery platform to which the heavy industry-minded Pacific Car and Foundry went to work on developing several pilot vehicles which ultimately produced a range of possibilities, the Army then electing to forge ahead with two promising designs that would become the M107 and M110 self-propelled artillery platforms. Key differences between the two would be the M107's 175mm gun and the M110's 203mm gun though both would utilize the same chassis and gun mounts between them for economical and logistical reasons. The initial batch of M110 vehicles was completed in 1962 and formal acceptance into the US Army and US Marine Corps inventory soon followed.