They worked just fine. The first real version of this particular sight was a turret sight; the British Gyro Gun Sight Mk.IIc
This was developed into the Gyro Gun Sight Mk.IId, which was for fixed gunnery in fighters.
The US copied the Mk.IIc and called it the Mark 18 (USN) and the the Mk.IId as the K-14 (USAAF).