I had the problem long time ago with the bm-31-12 and now i have the same trouble with the sturmtiger
What is the problem? Maybe a description of it, a screenshot or smth would help?

When having that tank chosen, head to Settings —> Ground Battles settings —> tank sights (top option). Here you can select default tank sight with range grid.
it just does not exist for me. I have had this issue for over a year now but specifically for the 15cm panzerwerfer. all default war thunder reticles that have range markers just simply disappear when actually using the sight. its extremely frustrating when I cannot range in a tank that heavily relies on it. I would use custom sights instead but they are all extremely outdated and do not have accurate range markings anymore, and the one that does only measures out to 1km.
Rocket armed vehicles don’t have standard gun sight, they heave their own individual default gunsights with the rocket range reticle on the right instead of on the left. You can find their own sight in that menu in the preset/reticle option.
There is no presets/ reticles for rocket gunsights though?
presets

reticles

and if you mean cross with a range scale. it doesn’t have the markings (I have specifically chosen cross with a range scale, not just cross, the range scales simply do not show)
It’s only visible on those specific rocket armed vehicles. They will have that sort of naming format in the reticle tab.
Cheers.
just had to go through and nuke the custom sights for the thing as it was showing a different sight
it would be amazing if each tank had its own sight with all different weapon calculation in the same scope but this would requiere some hard work to be done cuz theres a lot of vehicles, calliope does very well in this aspect for example by having both main gun and rocket pod ranges



