Savage bolt head bushing

Discussion in 'Advanced Gunsmithing & Engineering' started by Cloudrepair, Oct 20, 2017.

  1. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    Ok so I just did a bushing job on my savage bolt head.
    I used a 10-32 socket head cap screw, turned head down to 6mm thread milled the bolt head counterbored it .05 deep for .0005 press
    Screwed it in with RED locktight.
    perfect tight fit with .05 (of the screw head that was turned down) in the counterbore.
    I did drill and ream the hole in the screw in the mill while I had it at work to make sure I was in the center of the screw.
    Turned the firing pin down to .0615 about .0015 fit to the drilled and reamed hole. Reset firing pin protrusion .040 put all back together. Then thought what am i forgetting and realized the bushing sealed off the gas port through the side of the head.
    So I guess I better take it back apart and drill or interpolate the hole back in there at least a smaller hole to center breakthrough? o_ORight?
     
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  2. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    A pic
     

    Attached Files:

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  3. Ggmac

    Ggmac

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    Nice job !
     
  4. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    Thanks Ggmac
    So what do you think stupid quistion, obvious needs to be done, not necessary?
    I ask because I respect you guys and I've never heard anything about it in any of the other threads about doing a bolt head bushing.
     
  5. Ggmac

    Ggmac

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    Anytime it comes to venting gas I say go for . Definately !
    I once read a article (very short ) from the guy that designed the savage 110 , he said if done again he would redesign the gas shroud . He was concerned about it restricting too much gas and the vents in the bolt head may not be able to vent fast enough .
    It's early and no coffee yet so I may have a few things messed up , but anytime you can vent gas , do it .
    Ah coffee is brewing , time to wake up
     
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  6. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    Thanks
    I was thinking same way
     
  7. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    Now another question related.
    Now that I have bushed the firing pin hole and pin diameter to .062 can it be beneficial to reduce firing pin spring by a coil or two for less weight and bolt lift?
    Without safety issue?
     
  8. carlsbad

    carlsbad Lions don't lose sleep over the opinions of sheep. Gold $$ Contributor

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    So how long was your bushing? it should be just longer than your firing pin fall to ensure the tip of the pin is captured.

    We discussed shortening the spring in a thread a while back. I actually did experimentation to determine the spring rate of a stock Remington spring. Spring rates are measured in lbs/in. Most springs are sold as "18 lb spring" meaning total load in the compressed state. I'll try to find the thread. I estimated in that thread what effect you would have from cutting a turn off a firing pin spring. Somebody was going to try it and report back but I haven't seen any results posted.

    But the bottom line is, not that your pin is smaller by over 40%, it takes much less force to dent the primer and weakening the spring should not be a problem. Worse that can happen is you start getting FTFs and you have to put a new spring back on. I don't think you'll have that problem unless you get carried away.

    --Jerry
     
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  9. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    Right now I couldn't tell you the length of the bushing but I do know the the tip is captured or stays in the bushing in a cocked state. Not sure by how much at least .050 maybe up to .100
    It works very well.
    I beleave I stayed with the same dimensions as it was before for the most part. It is locked up in my car and I'm out of town right now but if you like I can measure it tomorrow.
     
    Last edited: Jan 14, 2018
  10. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    This is on a older savage with a midlength bolt and action That didn't function hardly at all so i took a long action bolt body and cut to same length then retimed the cross pin hole to the newer bolt head design so it now uses the most common heads and barrels without the breach counterbore. So the spring length may not be the same as the others. I guess I could always remake the spring from a long action spring.
     
    Last edited: Jan 14, 2018
  11. carlsbad

    carlsbad Lions don't lose sleep over the opinions of sheep. Gold $$ Contributor

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    Here is the other thread I mentioned. the caluclations I did are for remington. You can do similar for savage.

    http://forum.accurateshooter.com/threads/firing-pin-spring-weight.3937015/

    If you want to measure your spring rate, build a test fixture for the spring to sit around, perhaps a piece of 5/16" rod in a vise. Put a washer on it. Put your spring on it. Put a washer on the spring. Put a pound or 2 of some sort of weight with a hole through the center on top of the washer. Measure the length of the spring. This gets the spring slightly compressed into the active region. Now put on a 2nd weight (w), preferably a little heavier, 5 to 10 lbs. Measure the change in length of the spring (x) The spring rate is w/x in lbs/inch.

    --Jerry
     
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