It produced the M50 Ontos, a small tracked vehicle with light armor and six recoilless rifles. The Army rejected the M50, but the Marines embraced it, putting it on the front lines in Vietnam.

Here’s What You Need to Remember: In a desperate bid to quickly get an anti-tank capability into the field, the Marine Corps enthusiastically embraced a project the Army had rejected: the M50 Ontos.

In 1950, the US Army and US Marine Corps started a joint project to build a light anti-tank vehicle. It produced the M50 Ontos, a small tracked vehicle with light armor and six recoilless rifles. The ...