When I edited JO, I could put these gun/ammo racks from misc_ list. However, after formating my comp and not installing JO, but JA instead, I can't put gun/ammo racks to levels as the entity list completly misses them. However, I'm certain that these exist in JA as I have seen them in levels. Where can I find them/add them?

I would suggest reinstalling Radiant. Every now and then it seems people complain they are missing entities in the menus. I haven't seen any other solution than reinstalling.

And yes, they should be there

I re-installed and iI couldn't find the ammo racks there. So I went to get the newest version... And it hasn't got them either.

So, any ideas? Add them manually perhaps?

Maybe you should back-up everything custom you have, then uninstall not only GTK but JA itself. Then delete the folders, and make a completely fresh reinstall. And also pay attention to the SP/MP mapping mode...

Sorry, but I don't have any really good suggestions here. Such things have never happened to me (like most of the rest of the problems people seem to be suffering with their editing software. I must be blessed or something...).

I switched it to MP mapping mode and then back to SP mode. That didn't take effect until my comp mysteriously crashed during editing... After that they appeared in the misc_ entity list. So did many other things I now realize missing before. So I guess problem solved. Only problem is that I saw them only as red boxes, so putting them to right place and aligning them is a bit hard...

Try to restart Radiant.

I tried restarting, but it didn't help... But I noticed two odd things. First, I have 2 gun_racks and 2 ammo_racks which seem to be identical... Secondly, when I open any of my old levels I can't add gun/ammo racks as they and some other entities are missing then.. I solved this by importing my old maps to a new empty map.