Ha, ha. In the 70s, an infantry unit in Okinawa had a M60 machine gun that was unserviceable (warped receiver), so they ordered a replacement M60. Except they clerk did not look too close at the National Stock Number and instead of a M60 machinegun, he ordered a M60 tank. No one caught the error until they unloaded the tank off the ship. Luckily for all concerned, the Tank unit on he island was short one tank (sent back for rebuild). So the tank unit got the new tank and the external machinegun on the turret was sent to the infantry unit.
I knew a guy that was peripherally involved in the incident. He said that a quick investigation showed that it was just an error and recommended no formal punishment, just maybe some lowered performance marks. The general at the time said no lowered performance marks and added something to the effect of, "Well, you might think it was an error but it improved the combat readiness of two combat units. So I am going to call it "Divine Intervention."