Can primers cause vertical stringing?

Discussion in 'Reloading' started by tlk, Aug 31, 2009.

  1. tlk

    tlk Well-Known Member

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    Can the variation within a given lot of primers cause vertical stringing? I was using some Fed 210s (standard stuff) and was getting 1/2" horizontal with up to 1.5" vertical at 100 yds. Changed it up to CCI (standard stuff again) and got groups that were almost round. Best group was 0.654". The 210s were an older lot (1999 :D) so I am wondering if this is the issue.

    I'll load up some more and shoot again tomorrow to confirm but just wanted to know if this is a possibility or if I am barking up the wrong tree. Would be great to solve this problem.

    Thanks.
     

  2. AJ Peacock

    AJ Peacock Well-Known Member

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    Any change in components can alter a load and change the groups. I'd verify the change and go from there. It's not likely that the older primers are a 'problem', just that they don't fit as well with that load.

    AJ
     

  3. lever-hed

    lever-hed Well-Known Member

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    what is the chrony saying?
     
  4. tlk

    tlk Well-Known Member

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    No chrony. Still in the first stages of load development and working through this stringing issue.
     
  5. Boss Hoss

    Boss Hoss Well-Known Member

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    Without knowing the velocity, you are wasting your time. I can think of many things that cause "stringing".

    This may hurt your head but read and understand this and you will be better off..



    Tips on Vertical Problems by Speedy





    1. A lot of rifles are muzzle heavy. Some rifles have too heavy a barrel and this causes vertical problems, especially those who shoot free recoil



    2. Firing pin coming out of hole in bolt in the cocked position. This will cause poor ignition. Take bolt out of rifle and look in firing pin hole. If you cannot see entire end of firing pin it has come out of the hole.



    3. Firing pin dragging in bolt or shroud. Listen to the sound when you dry fire. If not the same sound each shot something is wrong.



    4. Trigger sear too much spring. Hold trigger in firing position and push down on sear with your thumb. If it is hard to push down, this will cause vertical problems.



    5. Firing pin spring too weak or too strong will cause vertical problems. If you think this is the problem change springs and see what happens.



    6. Tightening front sand bag too tight on stock. When you try to pull rifle back by hand and rifle feels like it is stuck in the bag it is too tight. Rifle should move in sand bags evenly, not jerk or chatter when pulling back by hand.



    7. Action not level with top of stock running down at muzzle end. Rifle will recoil up at butt end causing vertical.



    8. The load that are shooting can too light or heavy and can cause vertical problems.



    9. Bench technique not same every shot. One example, should against stock one shot and not the next.



    10. Bad primers – if getting vertical try other primers.



    11. Bad scope, if scope is bad from shooting vertical, if you change your load in anyway and vertical goes away it is not your scope.



    12. Rifle not balanced, it does not recoil right, jumps in bag. If rifle is built properly this will not happen.



    13. Some stocks are very flexible. This can cause vertical.



    14. Front sandbag too hard. I personally have never had a rifle that will shoot consistent with a rock hard front sandbag. It always causes vertical or other unexplained shots.







    Other Tips:



    1. Head on front rest loose. A lot of rests have movement even when you tighten them as much as you can. This can cause unexplained shots.



    2. Some 30 mm scope rings are not getting tight enough to hold scope. Scope slipping in rings under recoil. This will cause point of aim movement.



    3. Keep shell holders clean, in press and priming tool. I have seen so much dirt in shell holders that cases are sized crocked on body. Also primers cutting primer pockets bigger shaving brass as you seat the primer.



    4. Whenever you can, set up so you can load watching conditions on the range as you load your ammo. That way you will be aware of any changes in conditions since your last group and you will be mentally prepared for the new condition.



    5. Learn to look at whole field of flags, not just the row in front of you. A lot of times conditions change away from you will cause shot to go out of group before change in condition shows up in front of your bench.



    6. When you chamfer the inside of your case necks make sure they are smooth enough that they don’t peel jacket material off when you seat the bullet.



    7. I see people walking around with case necks turned up in the loading block. A lot of the time there is condensation dropping from the roof of your loading area. If one drop of water gets in case you are in trouble on the shot. How many times have you had a bad low shot when it has been raining and you have been walking around with your cases turned up in your block?



    8. Learn to keep head down and follow through when you are shooting each shot.



    9. I hear a lot of discussion about low shots in a group and apparently this occurs a lot on the fifth shot. If it is your 5th shot most of the time you can bet you are doing something at the bench.



    10. If 5th shot is a problem, which everyone does at times, we do what I call wishing the last shot in. We just aim, pull the trigger, and do not worry about the wind flags.



    11. This year alone I have seen nine lock rings on scopes that are not tight. Guess what that does to your group? Make sure yours are tight.



    12. When you realize that the wind is your friend you will become a much better benchrest shooter.



    13. Practice in wind, not in good condition.



    14. Pay attention to angle changes on flags. Even though you see the same color angle changes make a big difference in your groups.



    15. The longer you wait between shots when a condition is changing the more the condition change will affect your bullet.



    16. If you do not know how to read wind flags or have never seen a wind flag try to shoot your group with the flags all going in one direction.



    17. Equipment at bench has to work flawlessly. If it doesn’t get it fixed or get rid of it. We need all our attention on wind flags.



    18. Learn to shoot with both eyes open so you can see more of the conditions.



    19. Free recoil shooters should be sure rifle hits shoulder squarely on recoil, not on edge of shoulder or muscle of arm.



    20. Should have your own stool to sit on so that you can sit at the bench comfortably for you.



    21. Hunting rifle barrels – do not get cleaned enough. If you keep barrel clean it will shoot better for you. You should clean barrel good after every 10 to 12 shots.



    22. Most hunting rifles will not put first shot after cleaning with rest of shots. So after cleaning if you have a rifle that won’t group first shot shoot one fouling shot before going hunting or before you shoot for group size.



    23. When working up a load for your hunting rifle take your time and do not let the barrel get hot on you.
     
  6. tlk

    tlk Well-Known Member

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    Boss, I used that as a checklist - thanks. Yes, the chrony is coming.

    Today still no vertical and a 0.51" group CTC at 100 yards in a 9 mph wind. Hopefully I found my problem. Couple more days and I will know for sure.

    Its amazing how such a small change would (potentially) affect accuracy so much. Is it just a pressure change factor, or is it more like changing powder?
     
  7. pjracer

    pjracer Well-Known Member

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    you could retry the fed 210s and back down off charge some and see what happens.
     
  8. tlk

    tlk Well-Known Member

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    Yeah, I am going to redo some of my previous test loads in my notes to see if I get different results.
     
  9. Capt Kurt

    Capt Kurt Active Member

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    With all the responses you have your work cut out for you. I like to start simple and work my way up. Stringing can occur with the best of ammo and one wonders why. The number one cause of stringing is breath control. If your rifle has a scope mounted on it. Set the power on high mag. Get in to your shooting position and breathe in and out. Watch your crosshairs. You will see your crosshairs moving near vertical depending on your shooting position. I would venture to say you will find the same pattern of stringing on paper. Grouping your shots (amoung many other factors) is usually the ability to slow your chest movement and take your shot at the same point each time. Breath control takes practice and should become natural over time. Take notice next time you are at the range. And don't drink coffee before you shoot. Hope this helps. Captain kurt
     
  10. TracySes23

    TracySes23 Well-Known Member

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    Years ago, when I shot pistol competition, I noticed drinking coffee, alcohol or smoking the same day or the day before always affected my scores negatively. Even personal concerns would sometimes affect my concentration and I only shot informal competition weekly.
    I can't say it affected everyone like that, but it did me.
     
  11. Bart B

    Bart B Well-Known Member

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    A 30 caliber 180-grain spitzer boattail bullet leaving the muzzle at 2600 fps average with a 100 fps spread will have vertical shot stringing on target at 100 yards of about 2/10ths of an inch. A 1000 yards, vertical shot stringing will be about 40 inches.

    Primers have to be really bad to see vertical shot stringing at 100 yards. I don't think your stringing's caused by the load.

    If you're shooting your rifle hand held against a shoulder with the fore end resting atop something on a bench, your position, holding and trigger pulling technique can easily cause 1/2 to 1 MOA stringing in any direction.
     
  12. Capt Kurt

    Capt Kurt Active Member

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    Although several things can cause vertical stringing, generally vertical stringing can be caused by a hot barrel. As you shoot the barrel warms up and depending on the barrel size and caliber being shot, along with outside temperature the barrel will continue to heat up unless allowed to cool down. As the barrel becomes hot the stringing process starts. Each shot continues to heat stress the barrel. Always let the barrel cool down if stringing occurs. Rule of thumb, If you cannot hold the barrel with the bare hand and leave it there then the barrel is too hot and needs to cool down. Thin tapered barrels tend to be more prone to this condition then heavy bull stainlees barrels. Hope this helps.
     
  13. Bart B

    Bart B Well-Known Member

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    Sorry Captain, but that's one of the oldest myths in rifle shooting on this planet. It stems from this common problem with commercial factory rifles and barrels. But 'tain't so with rifles put together with all the right stuff.

    To many (hundreds, thousands) of long range competitors shooting 30 caliber magnums prone burning 65 to 70 grains of powder putting a 190 or 200 grain bullet down range every 20 to 30 seconds for 25 or more shots and never had even 1/2 MOA of elevation shot stringing way out to 1000 yards. Properly built rifles with properly stress relieved barrels do not nor never had vertical shot stringing problems. Best test of this was when someone put 40 shots from a Hart barreled Win. 70 in .308 Win. clamped in a machine rest down range once every 20 seconds or so. All those Lapua D46 185-gr. FMJRB bullets went under 2 inches on the 600 yard target.

    Most common cause is the barrel's fit to a receiver that has a high point on its face and as the barrel heats up, that high point puts a stress line in that axis off bore center and the barrel whips more in that direction. It's often in the vertical axis but can also be in any direction. Once in a while, someone puts epoxy bedding under the barrel's chamber and this will definitely cause vertical shot stringing as the barrel heats up; but not as much as a poorly fit barrel. Usually can be fixed by facing the receiver face square with the barrel tenon thread axis then using a shim washer between the barrel and reciever so it clocks in right for headspace and sight hole alignment.

    Arsenals testing good lots of 30 caliber match ammo shoot a couple hundred shots per test group. Every 20 to 40 seconds, a bullet goes down range in their test barrel. They all land inside a 6 inch circle at 600 yards. Not too shabby for such stuff that'll shoot under 1/3 MOA at 100 yards so tested.

    M1's and M14's shooting that ammo in one match werein 24 shots are fired in 50 seconds also shoot it that accurate. But the guy shooting them that fast and reloading once with an M14 or twice with an M1 cannot get the sights back on the target too repeatable from shot to shot so the groups on paper end up about 12 to 15 inches when so shot at 600 yards. Somewhat smaller at the 500 yard stage where as many shots are fired in the same time limit. And these rifles have thin, tapered barrels, not thick, straight ones, too.
     
  14. etisll40

    etisll40 Well-Known Member

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    The shooters skill is a big issue, so practice more, shoot slower...