During World War II, Hollywood joined in the war effort, big time. Then-actor — and future president — Ronald Reagan helped train pilots on how to recognize the Mitsubishi A6M "Zero" as one of the more prominent examples, but many others took part.
One was Mel Blanc. You never saw him. But you probably heard him. He was the voice of Bugs Bunny. Well, Bugs did his part for the war effort in some cartoons, including one that Warner Brothers pulled due to offensive stereotypes of the Japanese. America's favorite "wascally wabbit" is an honorary Marine as a result of his service on the screen.
But Blanc did more than just entertain. He also helped train some of the soldiers who were putting it all out there. Specifically, he helped train the gunners on heavy bombers. The B-17 Flying Fortresses had a lot of gun positions. Some of the ten-man crew manning them had other jobs (like the bombardier, the navigator, and the radio operator). Others just had to shoot.
No matter what, though, they needed to know how to aim their guns so that some Nazi or Japanese fighter didn't shoot their bomber down. In a 14-minute film, Blanc portrays a waist gunner on one Flying Fortress who starts out with some bad habits. Over that course of time, the trainees were given a crash course and the bare essentials needed to know how to aim their machine gun.
You can see this 14-minute film below.