Schlage C503-113 Pin Tumbler Spring (Including Primus), For Use With FSIC (pack of 100)

The C503-113 is the pin tumbler spring that sits above the pin stack in a Schlage cylinder, holding the top pins down against the plug so the cylinder returns to the locked shear line when the key is pulled. It's a genuine Schlage replacement part, and the same spring covers standard pin tumbler cylinders and Primus cylinders. If you are rebuilding or rekeying a cylinder and springs came out tired, kinked, or short, this is the part you replace them with.

Same spring. The C503-113 covers Primus cylinders as well as standard Schlage pin tumbler cylinders, so a locksmith servicing a mixed set of conventional and Primus cylinders does not need two spring part numbers on the bench.

Yes, the C503-113 is specified for use with FSIC. It's the spring for Schlage full size interchangeable core cylinders as well as conventional and Primus pin tumbler cylinders, which is what makes it the one to stock if your building runs an interchangeable core keying system and you rebuild cores in house.

A, AL and H Series. If your building is standardized on Schlage A Series knobsets, AL Series levers, or H Series hardware, one spring part number services the cylinders across all three, which is the point for an MRO buyer keeping a single line item on the shelf instead of three.

Sold as a pack of 100. Springs are consumed several per cylinder, so a 100 pack is bench stock for a locksmith or a facilities shop, not a single repair quantity. If you are fixing one cylinder you'll have plenty left over; if you rekey regularly across a portfolio, it's the right buy size.

Genuine, certified Schlage parts. That matters more on springs than it looks: spring rate and free length determine whether the pins return fully and whether the plug rotates smoothly, and a generic spring of the wrong tension is a common cause of a cylinder that binds or fails to return after rekeying.

No finish choice to make here. The C503-113 ships as one model with no finish or size options, so there's nothing to specify beyond quantity. Worth knowing because many Schlage service parts are finish specific and do require you to match the existing hardware; this spring is internal to the cylinder and isn't one of them.

Commercial. The C503-113 is a commercial door hardware part, matched to Schlage A, AL and H Series cylinders, which is the hardware that goes on commercial and institutional openings rather than residential builder-grade sets.