poor grouping

Discussion in 'Gunsmithing' started by steelshooter, Jun 16, 2011.

  1. steelshooter

    steelshooter Well-Known Member

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    A few years ago I bought a Rem 700 VSF in 308. It never grouped well, normally around 1.5-2 inches at 100 yds, so I had it rebarrelled by a reputable barrel maker. The new barrel wouldn't shoot well either at around 1.5 inches with my best reloads. The gunsmith wanted nothing to do with it and said it was just me and there would be nothing wrong with the barrel, but I was not convinced because I had other factory rifles which shot twice as well with half the effort. I then asked another gunsmith for advice and he said the action "looked" fine and it is probably the barrel. I bought a Tikka rifle to replace it and its the most accurate rifle i have ever owned giving consistent .4 inch groups so I decided to go for something a bit different and had the Rem re-rebarrelled to 20BR. Now I have a 20BR that doesn't group! The effort I put into the reloads should be giving me benchrest quality performance, but it doesn't. Experts have told me that blue printing is only fine tuning and wont bring a 1.5 inch group down to .5 inch groups, but surely I haven't had three bad barrels in a row on the same gun.

    Has anyone got any ideas other than throwing this gun in the creek?
     
  2. Gene

    Gene Well-Known Member

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    How is it bedded? Pillars? Scope and mounts tight? Reloads or factory ammo? How are you torquing the action screws and to what weight?
     

  3. steelshooter

    steelshooter Well-Known Member

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    The rfle is fitted with a HS Precision stock, has aluminium pillars, has been glass bedded (twice)and both the scope AND mounts were changed. The scope has also been proven on other rifles. The second barrel which was 7-08Rem gave best results with handloads, with extreme spreads all within 10 fps. factory ammo was way out at around 2-3 inches. The 20 BR handloads are also uniform in velocity with some groups having an ES of 6 fps, but groups still 1 moa. I would be very satisfied with .5 moa. Countless hours have been spent on load combos and seating depths etc with all barrels. Becoming reluctant to keep spending money on this white elephant.

    I appreciate you showing an interest.
     
  4. steelshooter

    steelshooter Well-Known Member

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    I forgot to add torque settings of 65in/lbs on the front screw and 35 on the rear, using a fat wheeler wrench.
     
  5. B-RAD

    B-RAD Well-Known Member

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    I use my calibrated elbow to torque my screws...
     
  6. Bart B

    Bart B Well-Known Member

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    What "reputable barrel maker" are you referring to that fitted one of their barrels that may be a sour one in your rifle?

    I've heard folks say things about ER Shaw and McGowen barrels that if put in print, they would burn holes in the paper (or screen if you read it on a computer). Other barrel makers such as Kreiger, Hart, Brux, Border, Shilen, Schneider, Chanlynn, Lilja and Obermeyer do a decent job of fitting one of their own.

    40 to 45 inch pounds of torque on the front and back Rem. 7XX action screws is usually about right. Folks have split factory stocks with 60+ inch pounds pulling that round Remmy receiver down into the wood; it works like a splitting wedge in a fire place log. Metal pillars prevent this.

    I'd check two things; irregular rifling around the throat and see if the barrel touches the stock anywhere. Rifling should look even and perfect and at least 1/16th inch clearance all around the barrel to the stock.
     
    Last edited: Jun 18, 2011
  7. ralfus

    ralfus Active Member

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    I have a rifle that shot .4"-.5" that went to 1.5"-2" after not being shot for a few months. Drove me nuts until I remembered replacing the action screws with allen heads just before putting it away. The new front screw was touching the bolt's locking lug just slightly. Worth checking out. Sometimes the little things get overlooked. Now that was on a Win 70 but maybe your front screw might be bottoming out on the receiver with an imperceptible amount of movement.
     
    Last edited: Jul 13, 2011
  8. highridge1

    highridge1 Well-Known Member

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    Torque the front and back actions screws to the same. I like 45 inch lbs. My rifles wouldn't group either if I torqued them so differently. There is a good chance this is the issue.
     
  9. Bart B

    Bart B Well-Known Member

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    This happens more than folks realize. Especially when the receiver's bedded against plain wood. Not so bad with flat bottom recievers (Win. 70) but round ones sometimes split the stock between the magazine cutout and recoil lug (any round receiver).

    Decades ago before epoxy bedding came about, smart competitive shooters would loosen their stock screws after a day's shooting. Then torque 'em up to the desired amount when back at the shooting place. I've known a few varmint hunters who did this but few other do it at all.
     
  10. sinarms

    sinarms Well-Known Member

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    steelshooter, send it to my shop, if I can't get that to shoot any better than what it does now it won't cost you a dime, I would even pay for the shipping that it cost to send it to me.
     
  11. Boss Hoss

    Boss Hoss Well-Known Member

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    There is so much more to accuraqcy than just a barrel! The Smith who does the work is very important however, there are so many other things that have a bearing on accuracy that it would take me an hour or two to type it all out.

    The shooter and ammunition are as important as equipment you are shooting.