Instead of typing all that out, if anyone ever wants to know ingredient costs outside of checking in the game itself you can go to your mods folder

Users/<username>/AppData/Roaming/SpaceEngineers/Mods/

and locate 1139824606.sbm

Open it with WinRar, 7zip or whatever you use to open archives.
Open the Data folder and look for CubeBlocks_<whatever weapon you're interested in>.sbc
Open that with your text editor of choice and read between the <Components> tags for an exact list of crafting materials.
Look in Blueprints.sbc between <Prerequisites> tags for ammo ingredients.
Spoilers: they all take iron and magnesium and some take a little nickel.

Hello! I found the ammo ingedients file on my dedicated server and modified the required resources a bit. But after restarting the server, in the game I still see the old values int the production menu.
Any idea what I could do to make it work? Thanks in advance!

In order to help, you would need to tell me exactly what you changed in exactly what files, and I would need some working understanding of how a dedicated server operates for this game with particular emphasis on how it handles modified files between loads.

Hi DrNiggle. I was changing the material requirements of iron and magnesium for the 900mm and 300mm Side Cannons ammo und the file: Data\Blueprints.sbc

About the loading mechanics of the server, I opened a ticket at the provider. It is still in progress but basically they want me to make sure I change the file only while shut down, otherwise it would reset the values...

Modifying Data\Blueprints.sbc will alter blueprint costs in game. I have tested this in a solo survival game just to double check. Please note that the values you input into Data\Blueprints.sbc are modified in-game by the "Assembler Efficiency" value under advanced game settings.

Most likely problems:
1. The server isn't updating the file correctly. Ship them the entire mod, modified to your liking, and get them to replace the existing mod.
2. The server is using the steam version of this mod instead of your locally modified file. Make sure the mod icon in the mods screen is a folder, not a steam logo.