Misfiring
Normally, an item that uses ammunition or charges only misfires on a natural 1. An item with this trait also misfires on a natural 2. An item can have this trait applied up to 3 times, misfiring on a natural 3 the second it's applied and a natural 4 the third time.
An item that misfires jams up and a wielder must use a Tinker action to to unjam it with a difficulty equal to 10 + double the weapon's tier. A jammed item does not perform its normal functions and is effectively an inert object.