Cutting down the Firing Pin SpringBack to Kel-Tec stuff
Note: After performing my own Drop test, I found that after cutting 7 coils off of my FP spring, my P-11 would fire from a 3 Foot muzzle first drop. So in other words perform this at your own risk, do you own testing, and DON'T DROP IT!!. I will be working on a solution of some sort for this, and adding any more info I come up with.
What I ended up doing was to making a V hammer spring pin that has a shallower V in it, as well as leaving the shortened trigger pull. Then I put in the Wolff extra power FP spring. I checked for light strikes in my pistol and did not have a problem (the primer strikes where pretty good still), but every pistol is different and will have to be checked.
Here are my origonal instructions:
After shortening and lightening the trigger pull, I also clipped 7 coils off of my firing pin spring, then filed the cut end down smooth (inside and out) so the firing pin would not drag on it, nor would the spring drag in the hole in the slide. I cut it down to help avoid light strikes because of the lighter hammer strike. If you were to only perform the lightening, or shortening (not both) this is probably not needed. You can check your pistol at the range and inspect your primer strikes on the spent casings. Also see if you get any light strikes, if so FP smoothing, and possibly FP spring shortening may be needed to get reliable ignition. I did not experience any light strikes in my first 100 rounds after both the shortening and further lightening of the trigger, but just wanted to make sure. You may or may not want to do this part. Some have said that going to light on the firing pin spring can lead to a slam fire. While this may be possible, I have never heard of it happening, and never experienced it myself.
The best way to check your pistol after shortening the spring this is at the range. DO NOT LOAD IT WITH LIVE AMMUNITION BEFOREHAND! First load a couple of mags with 1 round only. Chamber the round by dropping the slide (not easing it forward) from the Mag with the pistol pointing down range in a safe direction being prepared for it to fire when the slide closes. Now remove the round from the chamber. See if there is ANY mark on the primer from the firing pin. There probably will not be, but definitely should not be. If so do not shoot it, stop here and go home and order a new firing pin spring if you don't have an extra already (or get a new one and some lock tite out of your range bag). If not then get a mag with 1 round only in it and fire just one round at a time a few times to check basic pistol function (that 1 round fires correctly). Then load a couple of mags with only 2 rounds. Chamber and fire the first (and be prepared for the possibility that it may fire twice, don't shoot a hole in the ceiling!!), then remove the second live round from the chamber and inspect the primer for any evidence a primer strike by the Firing pin. If any is evident discontinue shooting until the Firing pin spring is replaced and tested again.
Another thing to keep in mind is that if you shorten the firing pin spring then test it and all is well, then add extra power recoil springs you must test it again!! Adding power to the recoil springs will add power to the slide closing which will add forward force to the firing pin. I have the wolf 10% extra power recoil springs and clipped off 7 coils, and everything works fine, but you must check YOUR pistol because they are all different.
It is (in my opinion) unlikely that a slam fire would happen, but it is possible, so should be checked. A full mag of 9mm (or .40) would be very unpleasant and dangerous going full auto unexpectedly.