Strange groups, Rifle? shooter? or load?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by goose, Dec 9, 2011.

  1. goose

    goose Well-Known Member

    Messages:
    190
    Joined:
    Dec 26, 2008
    Posted this on other sites, long story short I get two shots touching, then one (or more) an inch or more off, most of the time vertical. After some more shooting and load testing with 3 and 4 shot groups I've seen a pattern see pic. I adjusted my windage after the two "fowler" shots then shot the groups. [​IMG]

    I've been trying different bullets, powders, bipod vs sandbags and shooting styles of hard hold to more free recoiling. I will explain my rifle. Stevens 200 long action, 25-06 AI, shillen stainless select varmint contour, rifle basix trigger, recoil lug from northlander, BVSS take of stock, bedded. I do not have any type of cheek rest, which I suspect could be part of the problem. I have used the scope and rings (Vortex Viper 6.5-20) on two other rifles without getting this pattern. I have checked the action screws several times and they are tight, but I have not used a torque wrench. I don't shoot more that 5 shots in a row and do not let the barrel get too warm.

    I've been shooting 85 gr nbts and 90 gr barnes solids with H4350, RL17, H4831SC, and H1000. I'm using data from a Sierra manual, which I think is pretty conservative, and I have had no signs of pressure. I'm using winchester brass, neck turned and redding dies...Type S bushing fl sizing dies and Type D seating die.

    I have what I consider a solid bench made from some heavy tubing with two layers of 1/2 plywood which is anchored into concrete with 1/2" concrete anchor bolts. I have tried shooting off a bipod with rear sand bag and sand bags front and rear. Before shooting I slide the rifle slightly in the bags to see if it will recoil straight. I've been paying a lot of attention to my shooting form and have not figured out what my errors could be.
     
  2. jrw1976

    jrw1976 Well-Known Member

    Messages:
    205
    Joined:
    Mar 31, 2010
    Have you shot over a chronograph i bet that will tell the story. But if I had to bet it has to do with barrel heat.

    Jason
     

  3. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

    Messages:
    4,380
    Joined:
    Jan 31, 2008
    This screams consistincy issues to me, to much change. You need a torque wrench there is no way around it. You changing the rifle harmonics every time you mess with something. Set the rifle up with a torque wrench so you know everything is 100% true and shoot your groups at no less than 200 yards. Make sure your using the same rest every single time and wait 10 min between every shot.
     
  4. SBruce

    SBruce Well-Known Member

    Messages:
    1,786
    Joined:
    Oct 31, 2009
    Might also try a different bullet weight. Maybe something like 115 grn. Just to see if it's still showing the same pattern.

    If this is happening on a consistant basis, and is repeatable.......it makes me think something is loose or getting loose due to recoil, either internal in scope or with the rings/bases/action.

    Other things that often come to mind are barrel heat, but a good proper built barrel shouldn't do this with only 3 or 4 rounds, especially with a varmint countour tube. Sounds like you're letting it cool enough. Most competition tubes are shot at least 10, 20 or more rounds per relay and they don't exhibit poi change due to heat, if they did they would never win.

    If heat is causing poi change, and the rifle is bedded correctly, then something is wrong with the barrel or barrel steel IMO.
     
  5. liltank

    liltank Well-Known Member

    Messages:
    4,158
    Joined:
    Nov 3, 2008
    I found seating depth can get rid of your flier. I also found charge weight get rid of them too. Sometimes when I am shooting I will get the flier. As I increase the charge the flier goes away.

    Tank
     
  6. cfvickers

    cfvickers Well-Known Member

    Messages:
    372
    Joined:
    Jun 18, 2010
    Something on your rifle is loose. I would almost guarantee it. Possibly you are holding the rifle differently at times. It may be your loads, but if you know they are consistent, something is loose. I have an Encore that I have seen do exactly the same thing. I changed the barrel lug and problem solved. I just have to use a different lug with the 45/70 than I do the other barrels, it bangs them up pretty hard. It does not effect the accuracy of my 45/70 barrel, just the 25-06 and 22-250. I am betting something isn't right with your rifle. Some rifles however will place a cold bore shot in a completely different area than the rest. That 22-250 is 2 inches from my group with the cold bore shot, then the rest go in 1/2 inch. But ten shots over the course of a full day all from a completely cooled barrel will go inside a 1/2 inch as well. So at least I know where the first shot is going.