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One trigger pull, two shots

Discussion in 'Handguns: Autoloaders' started by Ian, Mar 2, 2003.

  1. Ian

    Ian Well-Known Member

    A bunch of the guys from the rifle & pistol club here at Purdue spent the day yesterday down at a local public range, where (unlike our on-campus range) we can use centerfire weapons. As usual, the cool guns all get passed around and tried out by everyone. So one of the guys is in the process of putting a few mags through my M1927 Sistema. On the second-to-last shot, he pulls the trigger, the guns goes "BaBANG," and two cases come flying out. Yeek! :what: I've heard of 1911s going full-auto, but never actually seen it happen! Fortunately, there were only two rounds lieft in the mag - as it was the second one went somewhere over the top of the berm. Needless to say, we packed the Sistema up right after that, and it's going to the gunsmith before it gets shot again. The last thing I want is for it to blow up firing out of battery.

    I'm particularly surprised by this because the fire control parts in this guy are pretty new. I bought the gun used, but the hammer, sear, trigger, and beavertail are all Wilson Combat parts. Since purchase, I've put probably close to a thousand rounds through it, with only a handful of malfunctions (all the fault of some slightly underpowered handloads).
  2. Al Thompson

    Al Thompson Moderator Staff Member

    Did you test the 27? Make sure it's clear (!!!), then cock it, pull trigger, while trigger is depressed, rack the slide to see if the hammer follows. If it does, off to the 'smith. If not, you may have had a bump fire - where your shooting buddy simply didn't get his finger off the trigger in time.

    Let us know the results....
  3. Pistolsmith

    Pistolsmith Well-Known Member

    When you test the 27 make certain that the disconnector is working. If it fails, usually the hammer only falls to half cock.
    Most often, when you get a double bump it is because the shooter is taking a very light grip and dainty trigger squeeze, and the pistol recedes into the muscles of the shooting hand and then bounces back against the trigger finger, firing another shot.
    It might also be that the jar of the slide slamming into battery displaces the sear from a too shallow or wrong angle of engagement. Check to see whether you have a 16 pound recoil spring or a heavier one that might cause trouble.
    Before you send the pistol off, test it with two rounds loaded. Aim at the bottom of the berm and take a very firm grip, lock your wrist and elbows and hang on almost until tremors begin. Chances are, it will function normally. If not, eliminate the possible causes one at a time until you determine why the double fire happened.
    If the second shot went over the berm, you are not holding the pistol firmly enough. When properly held, it will not rise that much in recoil. If in doubt, have an experienced shooter demonstrate double taps.
  4. El Tejon

    El Tejon Well-Known Member

    Ian, sounds like a bump fire.:confused:

    Have Steve at Walker's Guns over on Earl Avenue check it out just to make sure.:)
  5. popeye

    popeye Well-Known Member

    Replace the firing pin spring with a Wolf heavy duty. My Systema's was really weak. UNLOAD MAGAZINE AND CHAMBER. Replace mag in gun and retract slide till mag catch engages slide. Press slide release and let slide fall does hammer follow? Also replace sear spring. When I tried to adjust mine the leaf broke off. The 27's and Systemas are nice shooters but they are old and all springs need to be replaced. If you are not comfortable with 1911 dissassembly and adjustments by all means have a smith do it.
  6. Pistolsmith

    Pistolsmith Well-Known Member

    Your standard weight firing pin spring is OK unless, when you chamber a round, the firing pin "dimples" the primer. Heavy firing pin springs are OK to use with 18-20 pound recoil springs. Some old, beaten down hammer springs may give a light strike with a heavy firing pin spring and result in misfires.
    The advice given by a poster above to change all springs is excellent practice with a pistol from the 1920's.
  7. Ian

    Ian Well-Known Member

    First of all, I forgot to mention that the mainspring is already a replacement part as well. I'm not sure what weight, but it's not the original part.

    More importantly, 20+ tests resulted in zero hammer-follow-throughs. It would appear (much to my relief) that the incident was just a bump fire on the part of the guy shooting (who doesn't have much experience with 1911s, FWIW). I'll probably still have a smith check it out before I shoot it again, though (can't be too careful).

    Thanks for the help, guys!
  8. Handy

    Handy Guest

    This is another one of those "cool 1911 things" I've witnessed. While it is possible in any pistol, the 1911 seems to specialize in doubling. The SKS of pistol disconnectors.
  9. 10-Ring

    10-Ring Well-Known Member

    I've seen something similar happen 2X. Once was from bad trigger job & was on a full 7 round mag. I never found out why it happened the other time, only that the gun had been fixed and it never did it again.
    Good luck figuring it out ;)

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