Pistol can have infinite ammo. But the machine gun uses clips.
That's it. Three items. It's for a map I'm making. Flan has the ultimate weapon mod, but it's just WAY too many steps to get it working. Also, Flan won't allow bundling. It would be great to have a simple weapon mod with one addition to the Minecraft.bin file. Then, I could automate the install of the entire map.
Send me a message if anyone is interested in doing this. We can work something out since this is a specialized project.