Headspace Advice Needed

Discussion in 'Gunsmithing' started by winmagman, May 19, 2010.

  1. winmagman

    winmagman Well-Known Member

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    I need a little advice on where to headspace a .243 on a Savage action that I'm putting together for my sons to shoot. I've done 3 other barrel installs on Savages so this isn't completely new to me , but I usually just use a case since the other 3 are wildcats or never see factory ammo.

    This time I will be using a Go Guage since this one may have some factory rounds put through it. So what I need to know is, would you just turn the barrel in until it hits the guage and trust that tightening down the barrel nut gives you enough headspace? Or shim the back of the guage, and if so how much, then tighten down the barrel and barrel nut?

    Thanks for your input.

    Chris
     
  2. bigngreen

    bigngreen Well-Known Member

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    I recently re-head spaced my Savage 270WSM and I went with the go gauge plus one piece of tape which added .002. I made it snug on tape and when I checked factory cases I had .004 of head space on new cases with the same bolt drop as I had on the head space guage plus .002 of tape.
    That's all I know :)
     

  3. Loner

    Loner Well-Known Member

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    It's a go gauge, if your bolt closes you have enough headspace.
     
  4. J E Custom

    J E Custom Well-Known Member

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    With the savage action , use a go gauge and just snug the barrel against the gauge (Do not
    tighten) as you tighten the barrel nut it will loosen the headspace just a little. when you are
    though tightening the nut you can check it buy placing a .001, .002 , and a .003 thousandths
    shim behind the go gauge with a touch of grease to hold it to the gauge.

    When it wont close on a shim with out pressure it is head spaced the size down from the one
    that it doesn't want to close on .( The thickest it will close on with out forcing it).

    It should end up between .001 and .002 thousandths.

    If you use a factory round it can end up to tight or lose because factory ammo varies up to
    .010 to .012 thousandths in length.

    Use a head space gauge and make it right.

    PS; some use scotch tape with good results but if you are not use to doing it this way the tape
    will compress and give you false results.

    J E CUSTOM
     
  5. Gene

    Gene Well-Known Member

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    I buy only go guages. For no go, I cut a small circle of self adhesive mailing label - about .002" thick - and place it on back of the guage.
     
  6. winmagman

    winmagman Well-Known Member

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    Thanks guys,

    Wasn't quite sure about setting things up to accomodate factory ammo, appreciate the help. Now as soon as the go guage gets here I'll be putting the info to good use.

    Chris
     
    Last edited: May 22, 2010
  7. winmagman

    winmagman Well-Known Member

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    Well, things turned out about as well as I could hope for.

    Opted to use the Go guage without shimming, and am very pleased with the results. The calipers read 3.620 when I measured the Go guage with a head and shoulder guage. On brass that measured 3.621 the bolt closed as if the chamber were empty and on brass that measured 3.623 I had a slight crushed fit.

    I will say using the Go guage is a heck of alot easier and less time consuming than using brass.

    Once again thanks for the input.

    Chris
     
  8. Rustystud

    Rustystud Well-Known Member

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    If you don't use both a go and no go gauge every chamber you headspace is a "wildcat".

    Yes, it may work just fine.

    The one time when it does not and you have a case rupture and someone gets hurt or killed the first question you will be asked is who headspaced this rifle. The second question you will be asked is if you have liability insurance.

    I don't know of any licensed, and insured Gunsmith or Manufacture who does not use both a go and no-go "steel gauges. One of the first questions in every liability insurance application is weather you have ever chambered and headspaced any rifles. It has a second part that asked if you used "steel Go and No-Go Gauges". Saving $35.00 not buying and using a no-go gauge may cost you your entire lifes savings. The possibility of hurting a love one, friend or customer is is not worth cutting corners. There is a reason we use two gauges it makes the Chamber SAAMI or CIP spec.

    If one uses both the Go and No Go steel gauges you have followed the industy standard. There is no room for error. Anyone who suggest other than the standard could be considered contributory neglegent by a civil jury.

    It is easier to do it right from the get go.

    I am quite confident Len (the site owner/moderator) would want the information on this sight to be as safe and accurate as possible.

    Nat Lambeth
     
  9. Fitch

    Fitch Well-Known Member

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    I completely agree - use gages.

    I only work on my own rifles - I do it because I'm retired, have the time and tools, and really enjoy it. I've done several Savages, all with both go and no-go gages. After some experimentation on the first one I follow this procedure with Savages when I use the barrel nut, and so far it's always worked:

    • Hold the barrel in a barrel vise, put a ring of tape around the barrel out beyond the threads to hang the barrel nut wrench on so it won't scratch the barrel (don't ask), coat the tenon threads, receiver threads, barrel nut threads, and the nut side of the recoil lug with assembly lube. I use assembly lube because it is an extreme pressure lubricant designed specifically to prevent galling. I've also used Anti-sieze #5, it works fine, but like the way the assy lube feels better.
    • Screw the barrel nut on past where it will need to be, put on the barrel nut wrench past the nut (hanging from the barrel where the tape is), put on the recoil lug, make sure the little indexing lug is facing the receiver.
    • Disasssemble the bolt, strip the bolt head, reassemble the bolt with out the extractor and ejector. Screw the barrel onto the action with the bolt and go-gage in place till it just touches the go-gage.
    • Hold it right there, position the recoil lug and carefully bring up the barrel nut finger tight.
    • Take out the bolt and go-gage, put in a home made rear entry action wrench to hold the receiver in place (it doesn't take much to hold it) and torque the barrel nut to 100 to 125 ft-lbs on the standard tenon, 125 to 150 ft-lbs on the larger target action tenon. Yeah, I know, it's a lot of torque, but they never come loose, and they shoot just fine.
    The tenon always stretches ~0.001 to 0.002 inches near as I can tell. The go-gage will go bare but definitely won't go with a piece of cellophane tape on it, the no-go gage won't go at all. So far this procedure has given me a nice tight chamber.

    I can't imagine using a case to set headspace though Richard Franklin does it in his metal smithing video. Compared to a precision ground set of steel gages rifle brass has all the dimensional stability of a pink pearl eraser.

    Fitch
     
  10. bigngreen

    bigngreen Well-Known Member

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    Mr Lambeths advice is well taken, I may order both gauges next time, specially if I do something for some one else.

    Using a case is standard operating procedure on the Savagshooters forum. I chose to go with the gauge because I'm looking for a specific head spacing so it matches through to my reloading process. I started using the tape on the back as a No-go when I saw Gordy Gritters use that method in a video. I have read the No go is .004 longer than the Go so I set up for snug on .02 and no go at .003 so I'm in spec but not to tight.
    I found the factory head space on my 270 WSM wayyyyyyy out of spec to the tune of .009. Re-head spacing is top on my list for factory Savages now.
    Holy cow Fitch you put the gorilla on that torque, I believe the original factory torque is 75 ft-lbs. I go just over hand tight so I can easily remove it and swap a barrel.
     
    Last edited: May 23, 2010
  11. Rustystud

    Rustystud Well-Known Member

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    Barrels are tightened by gorillas at the factory because they don't want just anybody taking the barrels off. This is a liability thing.

    Savage barrel nuts are not engineered for more than about 50 ft lbs of torque. They will warp, and break if over tightented. I get them right then smack the wrench with a rubber mallet. Just tight enough that they want come loose. Some of the wrenches have a socket for a torque wrench.

    With good 2B threads they will tighten up to 50% thread contact at 50 to 70 ft lbs.

    Make sure you lubricate them well with a high temperature molly grease or use an anti seize.

    Rifles being rebarreled do not have to be factory tight to be safe. Especially actions that will see many barrels over their life span many times. One can eventually warp or pull out the threads by over tightening them.

    Nat Lambeth
     
  12. Fitch

    Fitch Well-Known Member

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    If one is looking for repeatability, I don't see how a case can be as good as a go-gage - a case will give (yield) more than the presumed desirable tolerance for a chambering job - they are pretty soft compared to a solid steel gage. I suspect most folks don't know what the dimensions are anyway, and if they use cases as gages they certainly won't be confused with any real data. Regardless of whether or not it's standard practice on a forum it doesn't seem like a good idea to me. Seems like the ignorance is bliss never to be confused with facts approach, but that's just me.

    Bingo!

    I have that video, and I have a ton of respect for Gordy. The tape works for him as a no-go and is tighter than a real no-go, but if he was checking a rifle that has problems for headspace I suspect he'd use a no-go if the bolt closed on the tape.

    I know it's a lot of torque, but it's only a preload of ~12,000 to 13,000 lbs using the sliding (not static) friction coefficient for good assembly lube. I torque it up using one smooth motion and a click stop wrench. Once I stop I don't try to move it farther. With good assembly lube the feel and motion are very smooth.

    The temperature difference between the barrel tenon (which gets hotter faster) and the receiver (which only gets heat that makes it across the relatively poor thermal connectio to the barrel tenon) grows the barrel tenon more than it grows the receiver which means the tendancy is for the threads to get looser as the barrel heats up. Probably doesn't matter for a hunting rifle that sees one round, maybe two, seodom three other than at sight in time. Might matter for a PD rifle that could get pretty hot, might matter for a match rifle that shoots 10 to 15 rounds per relay counting sighters and score rounds.

    Anyway, I don't want to worry about it so I torque it up. That's my story and I'm sticking to it. :D

    Fitch