Ranging Gun/Spotting Rifle - Are they viable?

[Deafening Silence]

Some tanks were equipped with a Ranging Gun/Spotting Rifle in the 1950's to fix their main guns onto a target by firing a tracer round from those guns which supposedly matches the ballistics of the main gun's projectile. Of course this was short-lived as laser rangefinders came about soon after.

So, how do I use a ranging gun on say, a Chieftain Mk.3?
Are they viable? Would this supplement the normal rangefinding option?

[Arizona Ranger]

Do a little thing called guesstimation

[Jaes]

Technically, yes they work.

Here's the thing though: When you fire your machine gun, you're giving away your position to literally everyone that saw your tracers. You would've been much better off sending a round down range then do your follow up shot to score a hit.

Or just spend the 6-8 seconds with the rangefinder so you can get a 100% surprise shot off.

[Katokevin]

For the most part, not really. Going to the Chieftain example, it's for HESH and you probably won't load it much. In theory, it's viable at closer ranges, but honestly, the time it takes you to fire a burst, adjust, burst again, and then be on target is probably going to alert the enemy and potentially give them that crucial moment to put a round into you.

If you know your rounds well enough, you really won't even need it in the first place, maybe at ranges of say 600-800m. There are times it can technically be helpful, but I've yet to really find many.

I haven't used one in a while, but I remember for a long time, it didn't really even match very well, often being a higher velocity than the HESH round, resulting in short shots at long range and shots high at close range.