Headspace Gauges Kit

Discussion in 'Reloading' started by Doug in Alaska, Apr 17, 2010.

  1. Doug in Alaska

    Doug in Alaska Well-Known Member

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    I'm shopping around for a set of headspace gauges for setting the amount of shoulder bump. I shoot .22-250AI, 7mm RUM, .338 Winchester Magnum, 7-08, 7mm Remington Magnum, 30-06, and a few more bolt rifles. I've been looking at the Hornady Lock-N-Load Headspace Gauge Kit. My biggest concern is the .22-250AI. Will this set work considering the 40˚ shoulder angle? Any recommendations?

    As always, thanks for your help!
     
  2. woods

    woods Well-Known Member

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    Hey Doug

    Yes the Hornady will work. I have a complete set and load for 22-250 through 375 Ruger with a 280AI in there in the middle. The place where the gauge hits on the shoulder is not important because the measurement is only relative to the other measurement. IOW it would not matter if you got a measurement on new cases of 1.575" on the 22-250AI or if you got a measurement of 1.585" because your measurements on the fired cases would expand the same amount.

    For example

    new case 1.575" - once fired 1.590" = .015" headspace

    or

    new case 1.585" - once fired 1.600" = .015" headspace


    See the difference which is the actual headspace or could be the amount the shoulder moved on the first firing is what matters, and that will be the same no matter where on the shoulder the gauge hits.
     

  3. boomtube

    boomtube Well-Known Member

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    Woods is correct, the LnL, etc, case tools don't care what the shoulder angle is.
     
  4. Doug in Alaska

    Doug in Alaska Well-Known Member

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    Thanks much guys! Do you find bumping .003" sufficient for hunting rounds and bench rounds alike? Will this also be the magic number for my belted magnum cases?
     
  5. woods

    woods Well-Known Member

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    I prefer .001" with a very slight crush fit. .003" leaves the case a little loose in the chamber and will slowly lead to more case stretching at the pressure ring.

    YMMV
     
  6. Doug in Alaska

    Doug in Alaska Well-Known Member

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    Thanks much for your help, woods!
     
  7. boomtube

    boomtube Well-Known Member

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    "Do you find bumping .003" sufficient for hunting rounds and bench rounds alike? "

    For hunting 3 thou would be okay. But it also leads to a bit more case stretch than I prefer. For my bolt rifle varmint/target loads I prefer to neck size OR FL size to restore the location of the fired shoulders. The shoulders of fired cases are already 1-2 thou off the chamber shoulder.

    You will find it's virtually impossible to consistently put shoulders at any specific point due to normal variations in case spring-back. I try to keep my MAX case (shoulder) lengths at whatever I want and simply accept those which are a couple-three thou shorter.
     
  8. Doug in Alaska

    Doug in Alaska Well-Known Member

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    I've been working with the .22-250AI cases and the measurement I get when measuring unsized, fired brass is 1.5885". If I back the Hornady die off a quarter turn as suggested in the manual, the resized case ends up 1.5885", same as unsized, fired brass. This brass fits the chamber without any resistance. I guess this tells me I am not bumping the shoulder back. However, I expected feel resistance when closing the bolt. Any suggestions?
     
  9. woods

    woods Well-Known Member

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    How many times have you fired the cases. It takes 3 or 4 firings most times before the case shoulder has expanded to hit the chamber shoulder. For instance these are measurements on my 30-06 cases and are pretty typical

    new cases - 2.040"
    once fired - 2.0485" (neck size only)
    twice fired - 2.050" (neck size only)
    3 times fried - 2.051" (slight crush fit, neck size only)
    4 times fired - 2.0515" (crush fit)

    then I push the shoulder back with a body die. For each subsequent firing after that I neck size with the Lee Collet and set the shoulder back to 2.051".

    So if you are sizing once or twice fired cases your cases may not have fully expanded yet.
     
  10. Doug in Alaska

    Doug in Alaska Well-Known Member

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    Thanks for the quick reply, woods. I believe the brass has been fired three times. Maybe a time or two more before I need to worry about bumping the shoulder?
     
  11. woods

    woods Well-Known Member

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    It is harder to feel the crush fit in the smaller cases like the 22-250. The bolt kinda overpowers the smaller cases.

    If you start sizing the case body it SHOULD push the shoulder forward a little, sorta like squeezing a balloon. If you have a tight chamber and a loose die then that effect may be minimal.
     
  12. boomtube

    boomtube Well-Known Member

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    "resized case ends up 1.5885", same as unsized, fired brass. This brass fits the chamber without any resistance. I guess this tells me I am not bumping the shoulder back. "

    The gage is indeed assuring you that the shoulders aren't being pushed back.

    Mr. Woods is correct, it's an FL sizer squezing the case body that pushes a shoulder forward, not the firing; that's part of what your gage is telling you. A neck die isn't supposed to touch the case body.