From Pathfinder Guns & Gears, which isn't enabled.

Persistent Lodestone

ITEM 7

CONSUMABLE MAGICAL TALISMAN

Price 55 gp

Usage affixed to firearm with a reload of 1

Bulk —

Category talisman

Usage affixed to a firearm with a reload of 1

Activate (concentrate)

Trigger You miss on a ranged Strike with the affixed weapon using an ordinary 0-level piece of ammunition.

This small magnetite block is attached to the barrel of the firearm by a thin metal wire drilled through a hole in its center. When you activate the lodestone, the ammunition from your missed shot is immediately recalled to your firearm, allowing you to fire again without reloading.

Pathfinder Guns & GearsORC