This FP spec spring is the striker spring I have been using in Glock pistols since around 2008. In my experience I have found that it's easily the best and easiest thing you can do to improve the trigger in a Glock pistol. This spring will reduce the pull weight by around 1 pound and still provide reliability with your duty/defensive ammo. NOTE- in my experience Glock pistols are sensitive to primers- meaning that even with the stock spring occasional ignition problems happen with hard primers or primers that are not seated correctly/deep enough. Bulk ammo and inexpensive ammo can and typically do have hard primers. Duty and defensive ammo has requirements for "softness" of the primer to ensure reliable ignition. I have personally shot over 10,000 rounds of "duty" ammo with this spring with no issues. This is the spring that is in my personal G43. I do strongly recommend that you test for yourself with your defensive/duty ammo. If you reload, in my experience Winchester and Federal primers that are seated correctly are good to go with this spring.