Trying to dial in rifle

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by stonehands1, May 23, 2015.

  1. stonehands1

    stonehands1 Well-Known Member

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    Have a 6mmAI with 28" Benchmark barrel on a Mauser action. Seems like a well put together rifle. Very nice trigger and seems to shoot pretty good. But not as good as I hoped or expected. I bought the rifle used so not sure of round count but would guess 6-800. Have a Leupold vx3 LR with the varmiter reticle on it.
    I reload and have done everything as perfect as possible to make sure every round is identical. I am considered a very good paper shooter by my shooting buddies and have no problem shooting .250 groups repeatedly with rifles that are capable. But this rifle seems to be my nemesis. After 150 rounds trying to get the 87 grain vmax to shoot the same hole I'm about to go crazy.
    Have found that 49 grains of vv160 is right at the max and also most accurate. .030 off the lands is where this bullet likes to be.
    Almost every group looks like the one pictured below. I put 2 in the same hole or close to it and then 2 or 3 more in a different hole a half inch or so away. Any thoughts would be appreciated. Thanks in advance.
     

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  2. MudRunner2005

    MudRunner2005 Well-Known Member

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    Is the action properly bedded to the stock? Are the action screws properly torqued? Is the scope confirmed to be ok? Are the scope mounts and bases tight?

    The gun appears to group nicely, but it has a shift in the POI. Sometimes that's suspect of the bedding job, scope issues, or even needing to adjust the bullet seating depth.
     
  3. stonehands1

    stonehands1 Well-Known Member

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    The bedding job looks real good. Not that I've seen 100's of them but very uniform and clean looking. I will double check the scope but pretty sure it's good. Took it off another rifle that shot great but worth checking.
     
  4. Garycrow

    Garycrow Well-Known Member

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    Try a different bullet. I have a 6BR that an extremely accurate rifle with bullets it likes but it shoots 87 gr. Vmaxs into about 1" groups. There's no use in beating your head against a wall trying to get it to shoot bullets it doesn't like, try something else.
     
  5. Greyfox

    Greyfox Well-Known Member

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    Might be the scope. I had a Leupold VX3 B&C on a 270WSM several years ago that did the same thing. Drove me crazy. Changed the scope and the problem went away.
     
  6. AZShooter

    AZShooter Well-Known Member

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    My first thought is bedding. Even though it looks good I have a few ideas. I have two Mauser clones called Mark X. One is a 14 lb LR platform.

    First check all blind holes in the action for any bedding material. If the action screw bottoms out before the action is truly tightened you will get that sort of group. Same thing with an action screw that is too long.

    Make sure the action screws don't hit the sides of the holes in the stock. Drill them larger if necessary.

    Now for something that I have done that has helped. I like to rely on the bedding to support the action but don't like the bottom of the recoil lug to make contact. I have either removed some bedding or have removed some metal from the bottom of the lug. This prevents any rocking action.

    The mauser "pillar" in the front, that is part of the floorplate assembly can be a problem. I shortened mine to make absolutely sure it wasn't making contact with the bottom of the receiver and was only supported by the bedding.

    I also use a torque wrench. I use 40 in/lb front and 35 in/lb rear with the slotted action screws.

    Let us know what you discover.
     
  7. stonehands1

    stonehands1 Well-Known Member

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    Great tips thanks guys. I have lots of bullets I want to try... just hate to concede the fact that I can't make it shoot what I want it to shoot.
    Thanks AZ shooter. I'll give your suggestions a try.
     
  8. deadlift

    deadlift Official LRH Sponsor

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    Heres a few tricks to try: 1). loosen the tang screw and place your finger under the barrel at the tip of the forend where the tip and barrel meet, now tighten the tang bolt. You should have no movement on the finger touching the stock and barrel. 2). If its floated place a folded playing card under the forend tip till you get a small amount of pressure, then shoot it. And 3). find a smith to lap the carbon out and check with a bore scope till its all gone. 4). Go between 200-300rds between cleaning, I know it sounds weird but trust me in this one. What twist/bullets are you running? I will agree with the other guys, usually double grouping is a sign of stress somewhere in the "system".
    Chris
    Benchmark Barrels
     
  9. stonehands1

    stonehands1 Well-Known Member

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    Thanks Chris. I think I finally got the barrel clean. Spent another 2 hours scrubbing it yesterday. Used Sweets, Butches, and Boretech Eliminator. I finally have clean patches!
    I have done the card trick on small diameter hunting barrels with great results in the past. Actually re bedded the front of the stock with about 7 lbs of up pressure after it was dry.
    Are you suggesting that I should do the card trick on this one as a permanent solution or as a indicator to where the problem may lie.
    Thanks
    Troy
     
  10. Rick Richard

    Rick Richard Well-Known Member

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    Chris,

    I have heard the same thing about not cleaning until the accuracy begins to diminish. It's just contrary to what most of us have been brought up to do. I find myself not cleaning after every range session now, but it is hard not too.

    Rick