[notes 1] Originally designated Artillery Rocket XM31, the first unit was tested on 29 June 1951, with the first production rounds delivered in January 1953.

The first Army units received their rockets by year's end and Honest John battalions were deployed in Europe in early 1954.

Developed at Redstone Arsenal, Alabama, the Honest John was a large but simple fin-stabilized, unguided artillery rocket weighing 5,820 pounds (2,640 kg) in its initial M31 nuclear-armed version.

The improved M50, with the smaller fins and more "rifling", had a maximum range of 30+ miles with a scatter on target of only 250 yards (230 m), demonstrating an accuracy approaching that of tube artillery.

The Honest John's bulbous nose and distinctive truck-mounted launch ramp made it an easily recognized symbol of the Cold War at army bases worldwide and National Guard armories in the U.S..

Conventionally armed Honest Johns remained in the arsenals of Greece, Turkey and South Korea until at least the late 1990s.

The project was in danger of cancellation "on the grounds that such a large unguided rocket could not possibly have had the accuracy to justify further funds.

"[7] On a trip to White Sands Missile Range, Toftoy met a Texan man who was prone to making unbelievable statements.

[12][13] Meccano Ltd. U.K. in its Dinky Toys range produced a model of the International Harvester Honest John missile launcher under the reference 665.