Bedding with an aluminum bedding block

Discussion in 'Gun Project Questions & Gunsmithing' started by Saxon11, Feb 22, 2011.

  1. Saxon11

    Saxon11

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    A few questions,

    I am bedding my 700 action in a bell and carlson medalist tactical with an aluminum bedding block.

    Would you reccomend devcon, or fiberglass?

    Also since it already has bedding pilliars, how much should I tighten the screws to sink the action down into the bedding material, and would this cause stress in the bedding job?

    My last question is, would it be a good idea to remove a little of the original material before I bed, that way there is more of the bedding agent in contact with my action?

    Thanks guys, I really appreciate all the advice.
     
  2. RonAKA

    RonAKA

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    I did my Savage LRPV which has a HS Precision stock with an aluminum bedding block. Before and after pics below. I roughed up the block, but did not remove any material. When I bed I used plastic electricians tape (and lots of it) to put a uniform pressure on the action from end to end (wherever there is bedding material). I did tighten the action screws to near normal torque, did the taping, and then backed off the screws so they were just snug -- near zero torque. This was done obviously right away before the Devcon started to set up.

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  3. Saxon11

    Saxon11

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    Thanks, did you see a gain in accuracy after bedding even though you had the aluminum bedding block?
     
  4. RonAKA

    RonAKA

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    I was mainly doing ladder testing before the bedding so no real groups to compare. Here is a pic of the first three groups out of it after bedding. Wish all targets looked like this. I am having an issue with about 1 flyer in 10. Don't think it is a bedding issue though.

    [​IMG]
     
  5. Dr. Vette

    Dr. Vette

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    If you really want to learn about bedding, read this thread:

    http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1167022

    I've followed the directions there and had excellent results. No stress, no nothing.
    I would not use screws at all, and do not use tape.

    Also take a look here:
    http://erniethegunsmith.com/catalog/i186.html

    He has several bedding tips too.
     
  6. rbertalotto

    rbertalotto Site $$ Contributor

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    How are you folks testing your bedding for stress?

    You need a dial indicator and a magnetic base. Attach the magnetic base to the receiver and the dial indicator on the top of the stock. Loosen the front action screw, there should be zero movement of the dial indicator. (You can also set this up on the barrel with the indicator touching the stock ). Next do the same for the rear action screw. Sometimes I see very little movement here if the barrel is real heavy, then I'll bed the first inch or two of the barrel to relieve some of the weight.

    It is simply amazing what a good bedding job will do to a rifle that has that "one flyer syndrome" ...or worse, "the two group syndrome" (two shots into one hole and three into another hole a 3/8" away........

    Three "B"s....Bullets-Barrels-Bedding.........You simply can't have accuracy without all three.........Period!

    If you see movement, your bedding is compromised or the screws are torqued too tight and you are distorting the bedding. It's all about the screws. This is why the BR guys do glue ins and don't use the screws.

    The biggest mistake I see time and again when I read about folks bedding rifles, is too much pressure pushing the action into the wet bedding compound. If the electrical tape or surgical tubing is too tight, it will ruin a possible good outcome.

    Most good accuracy smiths will not use the action screws to secure the action or align the action in the stock while bedding. It is nearly impossible to get a good stress free job with this technic. Plus, it's real messy and there are much easier methods using headless alignment screws.

    I use oversized, headless bolts that fit tightly into holes that are bored into the pillars I make. The holes bored into the rifle stock for the pillars have lots of room around them for movement and for substantial amount of epoxy.

    The holes in your pillars must be approx 1/32 to 1/16" larger in diameter than your stock bolts. You do not want the stock screws to touch the sides of the pillars.

    My pillars are chamfered 45 degrees and my bolt heads are the same. This centers the bolt in the pillar once everything is dry and the rifle is reassembled.

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    More Here:
    http://public.fotki.com/Rbertalotto/gunsmithing-reloading/

    Hope this helps!
     
  7. RonAKA

    RonAKA

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    Rbertalotto, I would suggest bedding an aluminum bedding block system is quite different than bedding a flexible wooden or plastic stock gun. Your biggest issue with the aluminum block and the quite viscous Devcon Plastic Steel Putty, is getting it to flow to create a true skim bed. If you look at my photo carefully you can see right through the bedding compound in some areas. What you are doing with the skim bedding is just filling in the voids. When you look at the size of a single shot Savage centerfire Target Action and the size of the aluminum bedding block, there is no way you are going to distort anything with some plastic tape. The purpose of tightening the action screws is get the Devcon to flow and not end up too thick. You back off the screws so there will be no residual stress.

    There are effectively no pillars in an aluminum bedding block. The block itself is one big pillar.

    There may be some merit in using the Liquid version of the Devcon instead of the Putty version.
     
  8. rbertalotto

    rbertalotto Site $$ Contributor

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    Understood......I've done dozens of stocks with aluminum bedding blocks........In many cases, for absolute precision, they offer no advantage in a GOOD fiberglass stock. They do offer advantage to a wood stock. But be aware, they add a second level of potential stress. The connection of the bedding block to the stock and the action to the block.

    I'm not sure you will find many record holding benchrest shooters using bedding blocks........I could be wrong, but I don't think so.

    Do the test.......Dial Indicators show no mercy...... ;D
     
  9. Saxon11

    Saxon11

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    great advice guys, if you don't use anything to hold the action into the barrel, won't the weight of the barrel tend to lift the back of the action up? I can't see how this would give you better accuracy, and even if you did prop up the end of the barrel, would that have an adverse effect?
     
  10. Saxon11

    Saxon11

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    also, by tightening down the screws, then letting them back off I can see how this would produce a skim coat, filling in only the gaps neccisary, but wouldn't it also produce air pockets because you are squishing out all the excess then allowing the action to rise again by backing off the screws?
     
  11. Saxon11

    Saxon11

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    rbertalotto, I checked out your link and noticed your pictures of your offset scope. I was wondering what the purpose of this is? I would assume that lets you use open sights as well as your scope, but is there any other benefits to it?
     
  12. BoydAllen

    BoydAllen Site $$ Contributor

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    Wrap some surgical tubing around the action and stock, and position the rifle so that it is vertical while the bedding sets.
     
  13. RonAKA

    RonAKA

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    About all I can say is that I observed no gaps. You can see every machining mark etc from the receiver in the bedding. I believe what you are depending on is the Devcon to actually flow under a minimum of stress. I generally follow the Richard Franklin method, and turn the gun upside down while the Devcon sets. I also think essentially nothing happens when you release the torque from the action screws. It just makes you feel good. I also think the term stress free bedding is a little over done too. There is no doubt there is going to be stress in the action later when you tighten the action screws. The trick is to have no physical distortion when you stress the action. To do that you have to be solid from the bottom of the action screw to the action.
     
  14. rbertalotto

    rbertalotto Site $$ Contributor

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    My long time shooting buddy, George, has diabetes. He is left handed and lost the use of his left eye......I built this for him so he can still shoot left handed but use his right eye. He was going to give up shooting before I did this for him. The last egg shoot, he came in second place!

    And I get my shooting buddy back!
     
  15. MGYSGT

    MGYSGT Site $$ Contributor

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    Before bedding, wrap some elect tape around the barrel for support in the channel. Adjust it for height and level. This will keep the barrel from tipping the action in bedding and as a side benifit, it will keep the barrel centered in the channel.
     

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