Trouble binding custom ammo to gun

Fine.

Incorrect. You only need two of those, the level file which specifies the PrimalGameData and the PrimalGameData file. Just return the GameMode Override in the PrimalGameData to default(little yellow arrow) or change it to point to TestGameMode.

This is your issue. You need to copy the weapon itself(this is not the Engram or PrimalItem file, there is another and it’s icon in the content browser won’t just be blue - it will look like the weapon itself.) to your mod folder and tell the PrimalItem file for your weapon to point to this new file - specified in the Weapon Template field. Furthermore, if you wish for this weapon to be able to accept the attachments like the laser, silencer, etc then you will also need to copy over the files for each of those and correctly re-reference them in your weapon’s files.

This is fine.

-WM