I've used the J-Ps in my 2 15-22s and my Sporter with zero issues. With a little light polishing, greasing with moly grease, and the crazy insane gonna blow my face off set screw mod(do NOT do this mod as it's inherently un-safe)I have some pretty nice FCGs.
One thing that I've read about is cutting off the hammer where it curves back to reduce mass and enhance firing pin action and reliability. Called "bobbing" the hammer.
To each their own. Do not mod the FCG unless you are well versed in the operation of a AR-15 FCG.
Hobie

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