Help - Vertical Stringing

JSTARSZ

Lefty's Rule
Full Member
Minuteman
  • Feb 6, 2008
    1,991
    198
    Wolftown
    I am not a novice shooter by any means but I am not the best either so I have started noting a trend in my shooting - the vertical stringing...I am shooting different rifles with the same loads. The loads are very consistent so I am sure it is not the loads but it is me. I shot at New Holland in PA this past weekend and have a 500 yard target shot with my Lefty Perseus. I also shot today at 100 yards as I was trying to zero my new scope with my GAP M40A3.
    Range004.jpg

    On the left is the 100 yard zero each with five rounds except the top one where I changed rounds and went from a 168 AMAX to a 175 Nosler that started shooting the five rounds and then added 1.5 MOA and went for the dot - 15 rounds (1 inch dots).

    The right larger target (12 Inch) is the one I shot this past weekend at New Holland, PA. Except for the one flyer at the 9 it is 1 MOA but I know I can get it tighter.

    What I noticed is that the little 100 yard issues are multiplying at the 500 yard line. I am shooting prone with a Bipod and rear bag and I see definitely string from the 100 to the 500 yard.

    Any helpful tips would be very appreciative.

    Range001.jpg
     
    Re: Help - Vertical Stringing

    Breathing is my first choice as well. Are you breaking the shot at the bottom of your breathing cycle and not holding your breath (someone told me air is free!)
     
    Re: Help - Vertical Stringing

    That is funny as that was exactly what my wife told me too. I suspect that is what it is too and I need to pay more attention to it.
     
    Re: Help - Vertical Stringing

    The bottom right on the 100yd target stringing from 10 to 5 is you moving your trigger hand while pressing the trigger, I do it quite a bit myself.

    As for the others and your vertical stringing, you may want to consider that you are anticipating and giving into the recoil (flinching). Alot of shooters will get this in which when the rifle fires you flinch and pull your shoulder away from the stock in anticipation of recoil. This causes the stock to drop and give you higher impacts on target or vertical stringing, common in shooters with light rifles or hard recoiling magnums?

    If you do not keep your sight picture during recoil of every shot I would say that you are doing the above, it is sometimes hard to keep your eyes open and watch you reticle during recoil. You will learn alot by seeing what and where your reticle goes during recoil, also sometimes hard to admit to having a flinch.

    The only other thing I can think of is bipod hop, now that I noticed that you are shooting off a wooden bench, try placing a shooting mat across (may have to fold to fit comfortable accross the bench) the bench with the bipod resting on top and your elbows keeping it in position. You will also have to load the bipod just like you were to be shooting on the ground.

    Also try to keep your shoulders and elbows square to the rifle and target, natural point of aim is just as important shooting from a bench.

    Hope this helps
     
    Re: Help - Vertical Stringing

    Actually I was working on trying to call my shots and sometimes I did it well while others not so good. I really appreciate your taking the time to discuss. I think I have a combination of small errors that can add and multiply at longer ranges. I think I am going to spend some time and money on taking my "game" to a higher level.
     
    Re: Help - Vertical Stringing

    Love the GAP M40 by the way, if you are ever in question on your reloads and want to compare to factory stuff, get a box of Federal GM match ammo. My GAP M40A3 shot 1/4" groups with ease shooting that ammo, then I had to work on getting my reloads up to speed.
     
    Re: Help - Vertical Stringing

    I'm partway through resolving the vertical stringing in my prone shooting. Consistently breaking the shot during the natural respiratory pause after exhaling was a big part of it. The surprising part was how seemingly inconsequential differences in position and trigger finger placement would throw the shot. I noticed this after I'd consistently put the first shot in the dead center of the target and subsequent shots would wander as I fidgeted and made slight changes to my position while shooting the string.

    —Andreas
     
    Re: Help - Vertical Stringing

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Andreas</div><div class="ubbcode-body">I'm partway through resolving the vertical stringing in my prone shooting. Consistently breaking the shot during the natural respiratory pause after exhaling was a big part of it. The surprising part was how seemingly inconsequential differences in position and trigger finger placement would throw the shot. I noticed this after I'd consistently put the first shot in the dead center of the target and subsequent shots would wander as I fidgeted and made slight changes to my position while shooting the string.

    &#151;Andreas</div></div> Interesting as that is exactly what I am doing. Glad to know I am not the only one. I have noticed that I am fidgeting while shooting and I am sure it is moving my position on the rifle slightly.
     
    Re: Help - Vertical Stringing

    Or the knucklehead behind the scope which I am pretty sure it is. But, I am going to take some FGMM with me the next range trip to check out the possibilities.
     
    Re: Help - Vertical Stringing

    I don't usually watch the Outdoorsman TV channels; they seem to be a bit more oriented toward the G&A crowd. Not that I have reservations about the G&A crowd, they just don't seem to share many of my interests.

    But I saw something that caught my attention.

    One of the presenters was sighting in a scoped slug gun off a rest and rear bag, and he was holding forend down into the rest with his weak hand.

    I mean, he was grabbing the entire barrel and forend just ahead of the scope bell. I flinched just looking it it.

    He was shooting one holers. Then he released the forend to show the difference, and the POI jumped up considerably. He didn't fire subsequent, but I suspect he would have ended up demonstrating some very noticeable vertical stringing.

    His explanation was that a slug gun responds differently to recoil; that the slower, heavier projectile consumes a lot more bore transit time, allowing the bore axis to be displaced upward during that recoil on a much greater level.

    He said that the gun does not recoil freely in teh field, but is influenced in the field by the shooter's grip on the forend, and that the zero he obtains his way corresponds a lot better to how the gun acually performs in the field.

    This triggered my nod reflex.

    I have 'regulated' non-adjustable handgun sights by adjusting the cartridge powder load and bullet weight to allow muzzle flip to guide the POI so it intersects the line of sight. Less powder/heavier bullet equals more transit time, resulting counterintuitively in a higher POI.

    Moreover, any influence which accentuates muzzle flip will also accentuate any vertical stringing tendency, shooter-induced or otherwise.

    The trick would seem to be to find some way to dampen vertical travel during recoil. I know this goes against the concept of allowing unrestricted motion and followthrough, but bear with me.

    Have a method that I use that accomplishes this, which involves the use of a bipod and a slack sling. I have posted it here many times, but recent PM's suggest it's time to do so again.

    The shooter sets up in a nearly normal fashion, but this time, there's not only the bipod and (optional) rear bag, there's also a sling strung fore/aft directly beneath the rifle. As the shooter addresses the rifle, they slip their weak hand between slack sling and the rifle, then reach back in their customary manner to manipulate the rear bag/rifle butt.

    They then lower their elbows to the ground as usual, but this time they also trap the sling against or even slightly above the ground.

    The sling length is adjusted properly when the body's upper weight asserts considerable downward tension against the sling, holding the rlfle downward against the bipod feet. It doesn not need to be swinging clear, and probably also does not need to support the upper body's weight completely.

    In this way the upper body's weight acts through the sling to very positively dampen the rifle against any recoil-induced vertical motion.

    I know this works from long term experience, even to the point where the shooter can observe at least the latter portion of bullet trace and subsequent bullet impacts at longer ranges. There is <span style="font-style: italic">no</span> bipod hop. Period.

    While logic suggests that this would work especially well with slower, heavier projectiles, as is the norm at longer ranges, there's also no real reason why it shouldn't work as well with lighter, faster loads, and closer in, too.

    At any rate, it's probably worth a serious try.

    Greg
     
    Re: Help - Vertical Stringing

    If you are resting the rear of the stock on the bag with the sling and sling stud attached, try shooting without it. Sounds like the sling is catching on the bag and causing differing recoil from shot to shot.
     
    Re: Help - Vertical Stringing

    Attached is a pretty good article for dissecting what may cause stringing.

    http://www.6mmbr.com/verticaltips.html

    One of the quickest ways to find out if it's too barrel heavy and may be a result of improper glassbedding or in need of glass forward of the lug is stick some business cards between the front part of the barrel and the stock (just enough cards to add a little pressure). Shoot it. If the groups tighten up, you'll need to have it reglassed to have a little glass pad forward of the lug.

    If you still get the same results, let someone else shoot it both ways to see if it's you or the gun.