https://en.wikipedia.org/wiki/240_mm_mortar_M240
Sort of interesting, dates back to 1973 deployment, by the Syrians, in the Yom Kipper War...
It takes 25 minutes to deploy, so radar guided counter battery fire is going to clean it's clock. Note that it's only deployed in Third World toilets, against enemies in sandals, with AKs.
Yeah. I got curious and found a video on YouTube. Interesting. Your point on counterbattery is spot on. It’d be useless against any technologically equivalent opponent with access to Arty.