Not holding open on last round.

Discussion in 'PF-9' started by Darthpaper 75, Jul 31, 2020.

  1. Darthpaper 75

    Darthpaper 75 Member

    Jul 31, 2020
    Recently aquired a new pf9 and took it to the range. Fired 50 rounds of armscorr through it and it ran fine and then switched to Remington pmc for 50 rounds and had a few double feeds and gun stopped holding open after last round about halfway through the box. I field stripped the gun and reassembled and didn't see anything wrong with the slide catch or magazine follower and it held open when I pulled the slide to the rear but not when firing last round of the magazine? Anyone have any suggestions on what the issue might be. I am hoping maybe it just didn't like the Remington ammo, but haven't had a chance to get to the range again yet to try anything different.
  2. Yankee_Rebel

    Yankee_Rebel Active Member

    Apr 6, 2020
    Worn slide stop notch in slide (less common)

    Weak magazine spring (more common)

    Worn magazine follower (more common)

    The magazine follower must engage the slide stop and push it up to engage the slide stop notch in the slide while overcoming the force of the slide stop spring (which is also the disassembly pin spring).

  3. Darthpaper 75

    Darthpaper 75 Member

    Jul 31, 2020
    I am going to assume that it is not a worn slide stop notch or magazine follower as it is a brand new gun. I did switch out the base plate on the magazine for the one with the pinky extension and I could not get 7 rounds in the magazine, only 6 so maybe I didn't get the magazine spring seated back in correctly when switching the baseplate out. Like I said it was fine for the first 50 rounds so 8 magazines ran fine and slide locked back as it should on empty. However about midway through the second box of ammo (about 3-4 more magazines) is when it started acting up. Gun was good and warm by then and probably a little dirty as well but I wouldn't think it should have been dirty enough to cause that particular problem. I will check my magazine spring before my next range visit and try to run some different ammo as well as some more of the Remington UmC to see if maybe it just doesn't like that particular brand.
    Yankee_Rebel likes this.
  4. buzzsaw

    buzzsaw Grand Poobah Supporter

    Sep 7, 2004
    Welcome to the KTOG!

    A weak mag spring in a new magazine is not unheard of. One of my P-32s came with one. One mag worked fine, the other didn't lock back. Changed out the mag spring, no more problems.

    If it's not a weak or improperly installed spring, it might be that the slide didn't go back far enough to lock back, even though the spent cases were ejected and fresh rounds loaded. A dirty gun has more friction, especially when it is new and tight, and Remington UMC isn't the hottest load out there. Shoot. Clean. Repeat!