The 40mm M79 Grenade Launcher used by the US famously in Vietnam, and in conflicts after that, had a radar system made by the Radio Corporation of America that would give an audio que to denote target range and speed. Almost like a mix of a policeman’s speedometer and a range finder, on a grenade launcher. It apparently worked up to 500 meters.
Traffic enforcement was different in the '60s.
And this is for shooting down police helicopters!
So what, the device tells you the range, then you adjust the sights? (Or vice versa where you sight a place to shoot, and set the device to beep when a target is detected at that range?)
My understanding is that it would be the former. So you can ensure your first round hits.
Today we’d use a laser range finder. But back then lasers were something scientists had in their laboratories not something soldiers took to the battlefield.
