M50 762-mm Honest John Rocket on trailer, CFB Petawawa, Ontario. The Honest John was a large but simple fin-stabilized, unguided artillery rocket weighing 5820 pounds in its initial M-31 nuclear-armed version. Mounted on the back of a truck, HJ was aimed in much the same way as a cannon and then fired up an elevated ramp, igniting four small spin rockets as it cleared the end of the ramp. The rocket had a maximum range of 50+ km.