Board Thread:General Nerf discussion/@comment-6159573-20140112180701/@comment-1585211-20140112181753

Very little. The Vulcan isn't the greatest for mods anyways, however, luckily, there are still quite a few stores that carry the belt refill packs (at least where I live). You're basically going to need to track down some spare parts, either a home-made cocking pin or one taken from another blaster, the belt pack, and while the ammo box isn't essential, it's nice to have. The ammo box and cocking pin could potentially be made using homemade items, but you wouldn't get the same strength or comfort.

It's a tough problem considering you've obtained a blaster that has little modding potential and is unable to function.