If someone really wants to make a replica, the gyroscope in that (1960 something) original is just an little iron flywheel attached to a fairly high rpm electric motor (probably 24v going off to 4 6v lantern batteries in a belt rig laying on the ground). It's a one axis gyroscope in line with the bore. It would basically act like a compensator. You'd aim, then engage the gyro (there's a toggle switch). It did work, but weighed like 20-25 pounds between batteries, flywheel, and motor. They got almost the same effect from testing normal end of barrel compensators and promptly gave up. There was a similar rig for archery too at one point. They did get used on motion picture cameras, and adapted down in size to TV cameras and eventually camcorders and still cameras.