Go gauge alternative?

Discussion in 'Gun Project Questions & Gunsmithing' started by mram10, Jan 4, 2018.

  1. mram10

    mram10 Guest

    I have read about guys making go gauges from a resized piece of brass then filling it with lead or epoxy. Seems to make sense. Does anyone have any experience with this?
     
  2. Someoldguy

    Someoldguy Silver $$ Contributor

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    If you are planning to use this to check a chamber you are cutting, I would buy the gauge and not go that route.
     
    Last edited: Jan 5, 2018
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  3. Dusty Stevens

    Dusty Stevens COVFEFE Gold $$ Contributor

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    if you use normal cases and chamberings one gage may do many other cartridges. like a belted magnum gage covers a ton. theyre not much money in the grand scheme of things. to become a millionaire gunsmithing one must start out as a multimillionaire.
     
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  4. paperpuncher

    paperpuncher Silver $$ Contributor

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    Can it be done, sure. Should it be done? Why not just get the correct gauge and eliminate a variable that could cause you issues later
     
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  5. dsculley

    dsculley

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    When i built my 6.5x47L I used a new Lapua case to set my head space. Then you add 2 pieces of Scotch tape to use as a no-go gauge. My goal was to have minimal expansion and it worked. My fire formed brass grows by ~ 0.002". When I re-size this brass, setting the shoulder back 0.002" I am essentially setting it back to new brass dimensions. I have shot fire formed brass and new brass and can't tell the difference on the target. Some will chime in and say this is not the correct way to do this, but I like it and it works for me. I have no plans to sell the rifle. If I did sell the rifle, I would either disclose this to the buyer or rent head space gauges and re-set head space with them. I have Lapua brass from two different lots and have had no issues with the new brass chambering. If I did, I would simply run the new brass through my sizing die before loading.

    By the way, no need to put epoxy or anything in the case you are using to head space. If you don't have enough "feel" to set the head space without crushing the case then you either need to get head space gauges or have someone else do it. I would suggest you mark the case well and keep it for future reference.

    I know one gunsmith who sets his 6.5x47L head space a bit long (can't remember the amount he told me) to allow for more powder. He uses this rifle in F-Class and does well. I don't see why he doesn't just cut a chamber for 6.5 Creedmoor as he is almost blowing his 6.5x47 case out to CM capacity, but as long as he is happy....

    My process: Remove ejector and extractor from bolt. Thread barrel part way onto action. Insert case and close bolt. Screw barrel on until I feel a very slight resistance. At this point I tighten the barrel nut. Slide bolt back and then re-chamber. If it feels good, use 1 piece of tape on case head and re-chamber. Bolt should close but you should feel a sight resistance. Remove case. Remove tape and then replace with two layers. Re-chamber, bolt should not close. If you really try, you can crush the tape and close the bolt so this takes a bit of feel and common sense. At this point, recheck everything, case with no tape, case with 1 layer of tape, case with 2 layers of tape. Results should be repeatable. If I am not satisfied at this point, I loosen the barrel nut and start over.

    Caveat: I wrote this under the assumption that you will be hand loading. If I planned to use commercial ammo I would definitely use proper head space gauges.

    If you want to discuss this more, pm me.
     
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  6. 260 Ravage

    260 Ravage

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    I use exact prosecute as dsculley.
    great minds--------.
     
  7. fguffey

    fguffey

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    It is too bad you are not my neighbor, I have made shop calls where all involved were ringing their hands because they did not have a tool that would not indicate to the smith the length of the chamber even if they had the tool. There are at least three different ways to determine the length of the chamber with out a head space gage and their are ways to modify head space gages to measure the length of the chamber from the shoulder of the chamber to the bolt face meaning it is possible to measure the length of the chamber from go-gage length to infinity with one gage.

    Problem: Too many reloaders feel threatened by something they do not understand.

    And yes, a reloader that can measure the length of a case from the datum to the case head can use the case to determine the length of the chamber. And a reloader that can operate a press, die and shell holder and can measure the length of the case from the datum to the case head can size cases to fit long, short and medium length chambers. I have never filled the case with lead and or epoxy, I have never found it necessary.

    Reloaders spend too much time trying to convince each other the case has head space and they believe they can move the shoulder back, I cant move the shoulder back and reloaders that can cannot tell me how they do it.

    F. Guffey
     
  8. mram10

    mram10 Guest

    Great info guys. I was wondering how a resized case filled with epoxy could move when you are lightly letting the bolt fall or adding very little pressure. Also, aren’t I simply worried about the junction between the case sides and start of shoulder, not the neck junction?
     
  9. fguffey

    fguffey

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    It was decided to use a datum, before that the case body/shoulder juncture was used, some head space gages before SAAMI are stamped with the distance from the juncture to the case head. I know, there are many reloaders that can make a noisy argument it is not possible but I have verified gages and checked the distance from the case body/shoulder juncture to the case head.

    F. Guffey
     
  10. fguffey

    fguffey

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    The neck/shoulder juncture can be used if the reloader has a good understanding of the datum. Problem: It would help if the reloader understood he is not using 'the datum' and the tool he is using is a being used as a comparator.

    F. Guffey
     
  11. dmoran

    dmoran Gold $$ Contributor

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    fguffy_car1.jpg
     
    Last edited: Jan 5, 2018
  12. swd

    swd Yep that's me Gold $$ Contributor

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    This can work except that new brass if frequently quite a bit shorter than "go gage". I've seen some .007"+ short of "go". For your own gun it doesn't really matter, but it's something to keep in mind.
     
  13. Dusty Stevens

    Dusty Stevens COVFEFE Gold $$ Contributor

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  14. Dusty Stevens

    Dusty Stevens COVFEFE Gold $$ Contributor

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    "I dont know what you're doing but I can tell you're doing it wrong. I cant actually show you this headspace science but trust me I know and you dont." F. Guffey
     
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  15. Rustystud

    Rustystud Site $$ Sponsor

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    SAAMI requires steel go and no go gauges.
     
  16. Alan Warner

    Alan Warner

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    I see this question asked often. There is a very simple solution when you find yourself without a head space gage.
    Just do the math and measure to a known size steel ball seated in the shoulder to the end of the barrel. If you are not able to figure this out, you should not be working on ANYONE's rifle.
    Alan
     
  17. fguffey

    fguffey

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    SAAMI also says the case does not have head space, one forum member called SAAMI to tell them what I said, they were nice but nothing changed; the case does not have head space and the reloader claims they can move the shoulder back, they do not know how and they can not explain the process but they continue to bump the shoulder back.

    I measure the length of the chambers without a head space gage, I measure long chambers with short gages, I measure short chambers with long gages.

    I would find a reloader that can verify a head space gage more interesting than a reloader that is convinced nothing is possible.

    F. Guffey
     
  18. mram10

    mram10 Guest

    Great discussion. Either way I’m learning. I ordered a go gauge, but will test against an epoxy filled resized case on some old stock and let you know what I find out
     
  19. Dans40X

    Dans40X Welder

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    Alan,
    You'll have the OP(& others) so confused that they won't know what day of the week they're on!!
     
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  20. tom

    tom Gold $$ Contributor

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    It helps if you put on some music:p


    giphy.gif
     
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