Horizonal stringing

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  • Jimbo
    Unwashed
    • Jun 2015
    • 18

    Horizonal stringing

    I was doing some load development today shooting 8208 and 123 amax , 2.260 oal, alowing barrel to cool between 5 shot groups .
    started with 27.6 then 27.8 and 28gr. the groops got consecutively smaller up to 28gr. At 28 the groups were a little under 7/8 inch at 200 yds .
    When I moved up to 28.2 the groups went to almost no vertical but strung each shot further and further horizonal to the right with each shot . Group measured 1/4 vertical but 2 1/4 horizonal.
    Anyone have any suggestions?
    I am completely baffled sense the groups before were very consistent but adding .2gr would make it go so horizonal
  • Vasux86
    Warrior
    • Apr 2015
    • 108

    #2
    What was the wind doing?

    Comment

    • Jimbo
      Unwashed
      • Jun 2015
      • 18

      #3
      There was no wind , I did all my load testing from a bench with front adjustible rest and rear rabbit ear rest . I have had guns that would move this way from the barrrel heating up but mine was plenty cool . The loads Pryor to the 28gr load all had a little horizonal but nothing like this .the 28gr load shot all 5 shots into a small cluster (typical group )

      Comment

      • kmon
        Chieftain
        • Feb 2015
        • 2095

        #4
        Have heard before vertical stringing add powder, horizontal stringing reduce powder. Not sure I fully believe it but have seen more than once when getting above a node some horizontal stringing.

        Comment

        • LR1955
          Super Moderator
          • Mar 2011
          • 3355

          #5
          Originally posted by Jimbo View Post
          There was no wind , I did all my load testing from a bench with front adjustible rest and rear rabbit ear rest . I have had guns that would move this way from the barrrel heating up but mine was plenty cool . The loads Pryor to the 28gr load all had a little horizonal but nothing like this .the 28gr load shot all 5 shots into a small cluster (typical group )
          Jimbo:

          No offense please but are you a competitive shooter in any precision rifle discipline?

          I ask because if you were, you would have added that you called good shots but they didn't go to your calls. Or you would have described the wind conditions.

          Back 'in the day' competitive shooters would say that if you undercharged, you would get a vertical string and if you overcharged, a horizontal string. However, it wouldn't start in the middle and go one way only. Shots were distributed left and right or up and down. Yours went right only.

          My view, shooter error. First inclination is position -- the rifle settled back to the right after each shot or you moved the rifle right for each shot. Second inclination, you didn't correct for a left to right wind that was blowing from 2 to 6 MPH.

          Just my view based on your description.

          LR55

          Comment

          • Jimbo
            Unwashed
            • Jun 2015
            • 18

            #6
            I'm not above taking advice or correction from anyone so no offense taken ,
            I didn't mention wind because there was none .
            I have been shooting for almost 40yrs and feel I am not a novice shooter .
            I have shot some compeditively, mostly 22 benchrest where the lightest wind and environmental changes adversely affect shots along with proper technique is a must .
            Just looking for some opinions from others .
            I do admit I have only shot ar-15's for a couple years now and it does take some time to get comfortable behind this gun and it could very well be me but none of the groups before this acted this way .
            I apreciate any opinions given ,
            I am only trying to improve my ability and this is a great place to aquire knowledge.
            Last edited by Jimbo; 05-02-2016, 04:59 PM.

            Comment

            • lwminton
              Warrior
              • Nov 2014
              • 143

              #7
              I would suggest that you try to duplicate it but use a better rear support and see what happens.

              Comment

              • Vasux86
                Warrior
                • Apr 2015
                • 108

                #8
                I'm thinking along the same lines as others that your shooting position might be the culprit. Did you happen to see this trend with multiple shot groups or just one? Did the trend hold with anyone else shooting the rifle?

                If this only happened once, I have to wonder if something was off in you natural point of aim, parallax, firing hand grip, rear bag position, trigger finger position, etc. Basically, with a fluke like this I would do my best to eliminate mechanics before thinking the load or rifle are responsible. I've had weird things like this happen and it's usually because of something I did wrong. Sometimes I can identify the error and prevent in the future, other times I can't figure out what I did differently but the problem mysteriously goes away after I police myself.

                Comment

                • LR1955
                  Super Moderator
                  • Mar 2011
                  • 3355

                  #9
                  Originally posted by Jimbo View Post
                  I'm not above taking advice or correction from anyone so no offense taken ,
                  I didn't mention wind because there was none .
                  I have been shooting for almost 40yrs and feel I am not a novice shooter .
                  I have shot some compeditively, mostly 22 benchrest where the lightest wind and environmental changes adversely affect shots along with proper technique is a must .
                  Just looking for some opinions from others .
                  I do admit I have only shot ar-15's for a couple years now and it does take some time to get comfortable behind this gun and it could very well be me but none of the groups before this acted this way .
                  I apreciate any opinions given ,
                  I am only trying to improve my ability and this is a great place to aquire knowledge.
                  Jimbo:

                  Roger.

                  Honestly though, you did what we call 'flat lining' which is considered to be a pretty good thing. Sometimes when we shoot for groups at longer distances where the wind may be a factor that we can't contend with, we shoot and view the vertical string as the important factor. Yours was almost no vertical so I consider it a pretty good. Given no wind, stringing only one way horizontally normally means shooter error. I would certainly shoot a few more strings with that load at 200 or 300 and see if it holds.

                  And, you only increased the charge by 2/10th of a grain? No way it was your load or your rifle. I can not fathom a condition with a gas gun where 2/10th of a grain difference in powder charge would do anything that one could detect without shooting about ten or fifteen each five shot groups and carefully measuring them and figuring out the mean radius.

                  Anyway, I bet the load is just fine.

                  LR55

                  Comment

                  • mongoosesnipe
                    Chieftain
                    • May 2012
                    • 1142

                    #10
                    what trigger are you running if you are going from a bench rest trigger to a stock mil spec ar trigger that would cause a bit of a learning curve
                    Punctuation is for the weak....

                    Comment

                    • Jimbo
                      Unwashed
                      • Jun 2015
                      • 18

                      #11
                      I have a JP adjustible trigger set pretty light . I feel like it is more than likely me not a dressing the gun correctly . I'm gonna load up some more and give it a try again .
                      Like I said I'm trying to learn every day and I listen to every suggestion the group has . Thanks

                      Comment

                      • earl39
                        Unwashed
                        • Sep 2014
                        • 18

                        #12
                        The rule is for vertical it is the powder charge and for horizontal it is seating depth.

                        Comment

                        • Kemosabe
                          Unwashed
                          • Apr 2016
                          • 1

                          #13
                          I know this is my first post but I'd like to throw my .02 in, My first thoughts after wind are trigger jerk, parallax or a broken scope. I've seen all of these do exactly like you describe. Did you re-check your zero with a proven load? I've had quite a few scopes go south on me and honestly you can't tell they're broke until you shoot a group with your zero load, unless of course you can shake it and hear it rattle.

                          Comment

                          • motoxxx_ryder
                            Warrior
                            • Mar 2015
                            • 180

                            #14
                            vertical is SD
                            horizontal is trigger control

                            thats everything ive used. at least in long range shooting.

                            Comment

                            • Klem
                              Chieftain
                              • Aug 2013
                              • 3507

                              #15
                              My money is on the shooting position.

                              Returning the rifle after recoil to the same position as the previous shot is important. F Class competition stocks are designed to track parallel to the bore axis to mitigate to likelihood that the shooter cannot (or does not) push the gun forward to the exact same position as the previous shot. Some shooters use a stop on the underside of the handguard when using a rest. You can push the gun forward until it comes up against the stock and can physically go no further. Or simply a mark or point on the stock that you push the stock forward to. Some Bench Rest discipline rules insist the stock must come off track on firing to make it more challenging, so parallel stocks are not permitted.

                              Good gun, ammo, and conditions are important but we must do our part too. If you can make everything exactly the same for each shot then it eliminates one more variable in the tight-group stakes.

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