New stock, Lost accuracy!!!!

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Jumpalot, Jun 12, 2006.

  1. Jumpalot

    Jumpalot Well-Known Member

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    Shooting a 300 WM Model 70 #3 Lilja barrel with 180 grn. Accubond over 75 grns. of RL22 at 3150 fps. Action was bedded in a Fajen laminated wood stock. Barrel was pressure bedded right above front swivel stud. Rifle shot consistent 1/2" groups. In an effort to lighten rifle, I purchased a Bansner stock. Same gunsmith bedded the action and pressure bedded the barrel. However, this stock is about an inch shorter in the forearm. And the pressure is now about 2" farther back on the barrel than it was. Now rifle shoots 1"-1 1/2". Can I get accuracy back by changing my load up or down? Maybe adjusting seating depth. Or free floating barrel. If I try free floating, can I just put a shim under the shank of the barrel to see if it works before ripping bedding out? Thanks in advance.
     
  2. sewwhat89

    sewwhat89 Well-Known Member

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    It sounds to me that with the shift in bedding point that you changed your barrel harmonics. I would go up, if pressure allows, and down a grain or two and see if you get your accuracy back. In the process, you may gain some velocity if you have to/can go up in powder charge to get your accuracy back. Good luck!
     

  3. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Is the stock one of Bansers Ultralight stocks? If so, the upward pressure may be significantly less then it was with the Laminated wood stock. THis can also effect things.

    From a rifle builders point of view, the need for a pressure pad at the tip of the forend is a bandage for a bigger problem in the rifle if this is required to make the rifle shoot well.

    With a properly fitted and chambered Lilja barrel, even a #3 contour, anything touching the barrel will in most cases detract from the barrels accuracy potential.

    With quality bedding the barrels should be floated in a properly machined barreled receiver.

    Because the new stocks forend is not as rigid as a laminated wood stock, varying pressure can be applied to the barrel from just your hold as well as how the rifle is supported. Shooting it off a bag will probably produce different groups then firing it freehand or off an attached bipod.

    Was the receiver accurized when the barrel was fitted?

    Kirby Allen(50)
     
  4. Jumpalot

    Jumpalot Well-Known Member

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    Kirby, The stock was supposed to weigh around 20 oz. unfinished. The receiver was accurized when barrel was attached. All groups are always shot off a bipod. Have other guns made by this gunsmith and all shoot around 1/2". Can I put something under the shank of the barrel to float the rest of it to see if it helps? Or does the whole barrel need to be floated?
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Unfortunately with a stock like that, I have found at times that if you put a shim in the forend most times it only displaces the forend and does not apply much pressure to the actual barrel. Barrel is stiffer then the forend.

    You can certainly try this though and see what happens, worth a try.

    One thing that has worked pretty well for me on these extremely light weight stocks if to bed the entire length of the barrel so there is 100% contact with the barrel. Just seems to stabilize things better.

    Something else to look at is the crown, did it happen to get nicked while working on the stock? This will always spoil fine accuracy.

    The main reason I do not care for a forend shim is that with light barrels, barrel heat effects them much more then heavier barrels. As such, as they heat up they are often influenced more by this pressure on the forend.

    Still, if it shot well before, the goal is to get it back to its original set up or something similiar as far as barrel vibration.

    You may want to try a ladder test and see what happens with the rifle. May just need a bit of load tweaking.

    Good Shooting!!

    Kirby Allen(50)