Well, believe or not, it seems that some of the older M&PFS 9's were giving inconsistent results on accuracy. I know, I had a brand new 2011 M&PFS 9 that was all over the place in accuracy. Surprised the heck outa me, I'll tell ya. Minute of "Bad Guy", sure, but tack driving? Not a chance. Did the different ammo deal, trigger clean-up, nothing worked. Sold it to a buddy as a duty weapon and I told him about the fine accuracy of the weapon being non-existant. I Went on down the road with my life so to speak, not troubled by it. About a year later, I started seeing these threads about the M&PFS 9 giving inconsistent accuracy in some pistols and great accuracy in others. I remebered how bad mine was, and all I had attempted to do to make it better to no avail. About the early or middle of 2013, I find out that S&W has done a PIP on the M&P, to include new twist rate barrels on the FS 9. Seems the newer models have much improved triggers(Thank you, APEX, for leading the way...lol.!), and different barrels in the 9's. S&W has apparently listened and updated their product.
It is entirely possible that a new "H" version gun won't shoot, but this is the first I have heard of it. If you have problems, of course contact S&W for help.
BtW, those of you w/ the "H" version gun just do not need APEX trigger parts. The "H" series pistols have very, very nice triggers in them w/ a very distinct trigger reset. Matter of fact, the new "H" version S&W sear looks not unlike the APEX sear. You can do the APEX stuff if you prefer, but shoot it first and see, the "H" guns are awesome in the trigger department, IMHO.
Thanx,Ofc.JL

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LEO, Instr, Armorer, Gov's 20