Not adopted by anyone. Demonstrated on Wiesel 1 weapons carrier. Turret was in development for Tiger UHT but project scrapped before fight testing; I don’t know if the prototype worked and the project was deemed unnecessary expense or if the prototype was unworkable.

 I think the big issue with RMK30 is that it’s a weapon with a particular niche and that makes it easy to cut as “too expensive”.

DavidPawley said:

Not adopted by anyone. Demonstrated on Wiesel 1 weapons carrier. Turret was in development for Tiger UHT but project scrapped before fight testing; I don’t know if the prototype worked and the project was deemed unnecessary expense or if the prototype was unworkable.

I think the big issue with RMK30 is that it’s a weapon with a particular niche and that makes it easy to cut as “too expensive”.

Its mostly bad timing.
The gun did work. It had been developed over quite some time and the test firings all had been successfull.
At the time the decision to continue development and how to actually use it had to be made no funding had been made available. So the system had been abandoned. After staying in limbo for a couple more years.

DavidPawley said:

Turret was in development for Tiger UHT but project scrapped before fight testing;

The entire UHT has been scrapped. The German Tigers are basically PAH2 standard. Which means they are focussed on anti tank warfare. No gun at all. To compensate later a .50 cal gun pod has been introduced. The usefullness of this can be debated.
Arming the UHT had been the main point of developing the RMK30. They wanted a more accurate gun and the full punch of 30x173. It certainly would have been a great system in this application.
Mounting it on Wiesel was mostly done because a test firing platform was needed and Wiesel was available. The weapon certainly could have been used to rearm 20 mm Wiesels with a much more potent weapon but the backblast was seen as a dealbreaker at the time. Because it would give the firing position away. Which to me sounds more like someone at a desk looking for reasons not to allocate funds came up with it.
Several other applications also has been proposed. One of my favourites is the submarine mast mount "Muraene". Which would have enabled a submarine at scope depth to engage targets with 30 mm AC fire.

The RMK 30 is one of the great "what if's" of the near past of the German military.
Some many promissing systems have been axed in the '90 and '00. Even in late stage or after the end of development to save some funding. While oders of magnitude more money has been wasted elsewhere. In several cases foreign systems had to be bought later for even more money to get the capability anyways. Its one of the main problems of German tax expenditure. They are only looking at cash flow. Not at overall cost. So they save a little now and congratulate themself for it only to have to spend conciderable more on the same problem later.

To clarify, I meant the turret prototype.

I knew that the RMK 30 worked.

Have Germany and America been exchanging procurement officials?;)