neck tension on a 7mm Allen

Discussion in 'Reloading' started by Ridge Runner, Dec 12, 2010.

  1. Ridge Runner

    Ridge Runner Well-Known Member

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    I'm having issues with neck tension, my cases have been loaded 6 times, annealed after the 5th firing, now I'm not an expert at annealing, but I've done it some so here's my question.
    I was losing neck tension on the 5th firing so I annealed all my cases, was using the gas kitchen stove (just don't tell the mrs) annealing time was approx. 1 minute, not getting the picture perfect annealing ring like lapua brass has but I'm getting the blue/gray color in splashes around the shoulder's edge, but I can still push the bullet into the case by pressing the bullet against the loading bench.
    I can't believe I'm over annealing but is it likely I'm under annealing them?
    appreciate your thoughts and thanks for your time
    RR
     
  2. royinidaho

    royinidaho Writers Guild

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    If anything I would suggest that you may be under annealing. I've done the "over the stove" method over years. The learning curve included burned finger, burned fringes on wife's pot holders along with flames once in awhile.

    When I finally got driven out of the kitchen I pretty much settled on a method similar to buffalobob's (there's a video around here some where.

    Wait till evening, turn off the lights an go for an even red glow at least to the base of the neck and see if that helps.
     

  3. JARHEAD1371

    JARHEAD1371 Well-Known Member

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    Here is the videos of the annealing the Buffalobob way. I tried it a while back and it's cheap, easy, and effective. CHECK IT OUT!!!
     
  4. Mikecr

    Mikecr Well-Known Member

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    Annealing doesn't increase tension, it reduces it..
    You have a sizing issue or misunderstanding.
     
  5. Varminator 911

    Varminator 911 Well-Known Member

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    If it takes a minute I'd be concerned about heating the case head too much. Softening the head of the cartridge case is extremely dangerous. I've got the cheapo Hornady kit and it takes about 7 seconds with a torch. That way the head of the case stays cool.
     
  6. Buffalobob

    Buffalobob Writers Guild

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    I doubt if any cartridge I load would pass that test although I don't know how hard you are pushing. However I really don't know because I don't ever try to do that. I check to see if, with the base of the cartridge on the table, I can push the bullet down with my fingers withhout standing up and getting leverage on it.


    Annealing is the only way I know to get your neck tension back to within a suitable range using the supplied die. It was the 7AM cases that forced me to learn annealing and I just do it my way and that works OK for me. Perhaps the machines do a better and more uniform job but I am not the worlds greatest rifle shot so if my groups are in the 0.3 MOA range at 100 yards then that's just the limits of my skill with a rifle and there is not much use in acting stupid and believing differently.
     
  7. Mikecr

    Mikecr Well-Known Member

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    Again, annealing reduces the stress that provides springback, and tension.
    'Heat-treating' makes metal harder. This is not 'annealing', which always means to make metal softer(or stress relieved). Brass cannot be made harder by heating it--ever.
    Brass is always made softer by heating, and the only way brass can be made harder is to 'work' it. With softer brass(freshly annealed) there is LESS springback, and LESS tension.

    You typically know it's time to anneal when a few cases in a batch exhibit EXCESS tension, as seen with splitting necks or seating force variance.
    Annealing is then performed to normalize springback in that batch of cases, and NOT to increase tension. Your sizing/firing takes care of that.

    Given your annealing method described(totally wrong), and apparent lack of tension, the cause and affect is pretty clear. Cycle the brass a few times(Size/expand/fire) to regain normal springback, and stop annealing for a while.
     
  8. Buffalobob

    Buffalobob Writers Guild

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    You should have quit typing after the first post if you didn't know what you are talking about.
     
  9. Ridge Runner

    Ridge Runner Well-Known Member

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    less springback equals less tension?? WTH, mike how can that be? nevermind just wrote off any post where you give reloading advise.
    RR
     
  10. Mikecr

    Mikecr Well-Known Member

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    Well, before you write it off, you might consider that springback IS your tension.
    And that it's exactly all the tension you have.

    When you seat a bullet, you are upsizing a neck. What holds that bullet in place is the SPRINGBACK from this upsizing, which tops out at 1.5-2thou interference depending on the brass work hardness, and regardless of 'oversizing'.
    Don't believe me?
    Measure a normally sized & loaded neck OD. Pull the bullet, measure unloaded OD & neck down further an extreme amount,, say another 5-6thou under. Now seat a bullet. It will be very difficult to seat because of all the upsizing you're doing here, but once seated the loaded neck OD measures the same as before.
    So now, is there greater bullet grip than normal?
    NO THERE IS NOT
    Pull the bullet, and measure how much the neck springs back. It will be 1-2thou under, with the same unloaded OD as with normal sizing. That is your tension, and it's entirely springback.

    Now do the same right after annealing, and you will measure LESS springback after pulling the bullet.
    If you over anneal a case, there will be maybe a half thou springback, to none at all...
    This is LESS tension.
    Further annealing will not fix this. The necks will have to be re-work hardened to regain normal springback.

    That's about as much effort as I care to waste here...
     
  11. Ridge Runner

    Ridge Runner Well-Known Member

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    ok, my interpretation of springback

    you resize a work hardened brass, as you pull the case out of the sizer it springs back, that make sense?
    now an annealed soft case, doesn't spring back as much when you pull the case out of the die, make sense?

    now the case that doesn't spring back as much has a smaller hole to stuff the new bullet in, am I correct?

    so which has more neck tension? the one that sprang back or the one that didn't?
    RR
     
  12. Mikecr

    Mikecr Well-Known Member

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    To begin, seating force and springback are different and seperate things.
    If it springs back less on down sizing, it will springback less on upsizing as well, causing less grip on the bullet, even if harder to seat(single pass upsize).

    If the sizing was sufficient and similar in both cases(the bullet is still upsizing with seating), the case which sprungback more will provide greater bullet grip(tension). It is springing back from seating -to cause grip.

    The case with no springback MIGHT cause more seating force with greater required upsizing on seating(probably not). But it will also provide LESS springback to grip the bullet once seated, because it's softer.

    I know, we describe bullet grip as tension, which is described as an interference fit..
    This is just another of many assumptions we make, that are wrong.