When I was testing your mod on a map where I already had researched the atomic bomb I didn't get the recipe for the atomic artillery shells. However, the atomic artillery shells were displayed in the tech-tree under atomic bomb. And i was able to spawn them via the console.

The recipe requires Rocket Control Units and as such the recipe may well not display without the Rocket Silo being researched also.

I shall attempt to test this myself but let me know if you notice the recipe appear once you acquire the Rocket Silo tech.

Disregard that, I hadn't created a migration script to retroactively add the recipe to the game if the technology was already unlocked.

In the process of doing that now a fix should be up in ~5 minutes.

Thanks for the quick response. I will let you know if this has fixed my issue.

Now it is working properly. Thanks a lot.