The Mark II Gyro Sight demonstration on the Spitfire. The Mark II Gyro Gunsight was the first gyroscopic gunsight to see widespread service with the RAF. It was first tested in late 1943 with production examples becoming available later in the same year. The Mark II was also subsequently produced in the United States as the K-14 (USAAF) and Mk18 (Navy).
The gyro gunsight was a very clever little piece of engineering that gave the average fighter pilot a pretty good chance of knocking down enemy aircraft. It vastly improved the accuracy of aerial gunnery among the broad crowd of Allied fighter pilots. It didn’t come into general use until fairly late in the conflict, mostly fitted to Mark XVI Spitfires, although Mark XIVs were occasionally seen with them too.
The gyro sight remained the principal aiming method in gun/cannon-equipped fighter aircraft until well into the 1970s. [Wings magazine, via Tim Prosser]