The firing pin spring is the part a dry-fire habit kills. Every trigger press in the living room is a cycle on it, and a tired spring turns into light strikes at the match. JP’s braided version is built for shooters who put a lot of presses on a JP-5, live or dry.
JP’s claim is about three times the life of the standard spring, from the braided wire construction. It is the upgrade JP fits as standard in the JP-5 Maintenance Kit, and the reason to buy it alone is to have spares without the rest of the kit.
One thing to know: JP states this spring is specific to the JP-5 and is not compatible with the H&K MP5. A shooter with an MP5 should not buy it for that gun.
The trade-off is small. Twenty-five dollars for a spring is real money, but it is cheaper than a lost stage to a light strike, and a spare takes no space in the bag.
