Target Sports

If the bore was damaged can the gun still shoot consistent groups?

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  • heavygunner8

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    I suspect I have a damaged gun bore on my new Sig P227. It's consistently hitting the same spot (lower left point of aim). I've let range officer shoot this gun, and he has the same result, its always hitting lower left point of aim despite the fact that the sights are centered correctly. The reason I suspect there is a damaged bore is because of the weird discoloration about 1/4 inch from the crown. Please see the below picture. I really hope I am wrong, though.

    vCK7oQB.jpg
    Guns International
     

    oldag

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    Can't really tell anything from the pic.

    Is the rear sight adjustable (not familiar with that model)? If they are both fixed, send it back to Sig.

    Sounds like you are getting consistent groups, just not on the bullseye. That is usually a sight issue.
     

    Bozz10mm

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    I don't really see anything that unusual in the photo. At what distance are you shooting, and how much low and left is the POI?
     

    pronstar

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    $20 for a laser bore sighter might reveal something amiss, methinks...?


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    diesel1959

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    you say the sights are "centered correctly". The object is not to center the sights on slide, but to adjust (or drift) them to bring the point of impact to the point of aim. The rear sight could very well not appear to be centered when casually examining the pistol; however, it's how she shoots that matters.

    As far as the point of impact being low, perhaps you can use a slightly shorter front sight OR use a higher hold--such as "cover what you wish to destroy" hold, like with an HK.
     

    heavygunner8

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    you say the sights are "centered correctly". The object is not to center the sights on slide, but to adjust (or drift) them to bring the point of impact to the point of aim. The rear sight could very well not appear to be centered when casually examining the pistol; however, it's how she shoots that matters.

    Wait. I thought if the sights looks centered it should shoot close to point of aim. Unless the barrel is somehow not properly sitting inside the slide. All of my guns have the sights centered and all of them except this P227 are shooting at point of aim.
     

    diesel1959

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    Wait. I thought if the sights looks centered it should shoot close to point of aim. Unless the barrel is somehow not properly sitting inside the slide. All of my guns have the sights centered and all of them except this P227 are shooting at point of aim.
    Nope. Every gun is an individual. Now I'm not saying it should be off wildly; however, the object is to drift your sights slightly to bring the point of impact to the point of aim. Sometimes that requires the sights to not be "centered" as you say.
     

    heavygunner8

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    Nope. Every gun is an individual. Now I'm not saying it should be off wildly; however, the object is to drift your sights slightly to bring the point of impact to the point of aim. Sometimes that requires the sights to not be "centered" as you say.

    Can you explain in terms of physics why this would be? Its not making sense to me why if the sights are centered, the shots might not be, assuming the barrel inside the slide correctly and the barrel has no damage.
     

    diesel1959

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    Can you explain in terms of physics why this would be? Its not making sense to me why if the sights are centered, the shots might not be, assuming the barrel inside the slide correctly and the barrel has no damage.
    EVERY firearm is an individual. Not every barrel is perfectly concentric and not every slide is perfect. And then there's barrel to slide fit and lockup. Even slight variances can cause the bore of the barrel to not be 100% perfectly parallel to the slides dovetails and hence, not 100% perfectly parallel to the apparently centered sight path.

    Driftable/adjustable sights get centered on the pistol as a starting point and then the user makes the necessary adjustments to bring POI to POA.

    How long have you been shooting pistols?
     

    diesel1959

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    Well, that would be a concern; however, he mentioned that others are getting the same result, which would indicate to me that with a consistent point of impact a consistent amount from the point of aim, that the sights are off and need adjustment.
     

    heavygunner8

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    EVERY firearm is an individual. Not every barrel is perfectly concentric and not every slide is perfect. And then there's barrel to slide fit and lockup. Even slight variances can cause the bore of the barrel to not be 100% perfectly parallel to the slides dovetails and hence, not 100% perfectly parallel to the apparently centered sight path.

    How long have you been shooting pistols?

    But to be so off from the point of aim at only 16 - 18 yards can't be normal, no? I understand slight variations between different guns, but the variation still cant explain that big of a difference.
     

    heavygunner8

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    diesel1959

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    But to be so off from the point of aim at only 16 - 18 yards can't be normal, no? I understand slight variations between different guns, but the variation still cant explain that big of a difference.
    it's absolutely normal. I have pistols where the rear sights are not even close to being centered for the pistol to "shoot straight".
     

    diesel1959

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    Have you put it in any sort of "gun vise" and locked it all down? Not saying it's the shooter or the gun, just wondering ............ trying to narrow it down.
    Excellent idea. It'll clearly show whether there is precision and then where the pistol is grouping relative to the intended point of aim.
     

    Dawico

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    It doesn't take much to change the point of impact. One part machined a hair off is all it takes.

    Most guns shoot straight with the rear sight centered but having to drift it a touch isn't all that uncommon.

    It shouldn't take much drift to get it to group centered. It may not even be noticable to the eye.
     

    jrbfishn

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    Look at it this way. If all guns shot to POA with the rear sight perfectly centered, there would be no need for windage adjutable sights on pistols.

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