neck tension and increased pressure

Discussion in 'Reloading' started by playersc, Oct 1, 2005.

  1. playersc

    playersc Member

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    1st question: As you increase your neck tension does the case pressure increase as well. 2nd question: Can you have too much neck tension say 0.010" and cause an unsafe situation. Thanks
     
  2. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    For a very simple answer to your questions.

    Question one: YES

    Question two: Possibly depending on several variables.

    What are you shooting and what load/bullet are you using?

    Kirby Allen(50)
     

  3. LB

    LB Well-Known Member

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    Yeah, and then if you are dealing with something like a 220 Swift, for instance, you have to decide whether to toss the brass, inside ream, or outside turn the necks. (or whether it is worth it, at this point) You get a lot of brass flow in certain cartridges. So, you have to be careful about your over all length and the possibility that the necks are being crimped when chambered. There is also a possibility that you have developed a "donut" inside, if you have already worked the necks. Just to clarify, you mean .0010 total neck tension, not wall thickness?

    What do your primers look like?
     
  4. Reloader

    Reloader Well-Known Member

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    I don't believe you could possibly put enough neck tension on any type of case to cause a dangerous situation as long as the load is safe. Think about how firmly Factory ammo is crimped, I'm willing to bet that even grossly undersized brass wouldn't hold a bullet as much as those types of crimps. I've seated bullets into cases that were sized w/o expander balls in FL sizers which actually made the bullet stretch the neck when seating and created quite a bit of neck tension. Those bullets are easier to pull than crimped rounds.

    Reloader
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Reloader,

    That is true, to a point. IF you start your load development with X amount of neck tension and work up from there you can produce safe consistant loads most of the time. Only problem with excessively heavy neck tension is that it is seldom consistant from one case to another so that is a problem.

    My warning was in reference to taking an established load and increasing the neck tension on that one load, pressure will increase significantly over the previous load.

    But I would agree mostly with your comment.

    Kirby Allen(50)
     
  6. Reloader

    Reloader Well-Known Member

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    Fifty, I see your point. I tend to think it probably has much more importance in Magnum Wildcats where the loads are being tested to the limits.

    Reloader
     
  7. LB

    LB Well-Known Member

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    It seems to me that there is a relationship between a tight necked chamber, and not so tight, but thickened necks caused by repeat firings. All things being equal, same load, (same reamer) but tight neck versus standard dimensions, the tight neck (chamber) should show more pressure signs? Whether this is achieved by tooling, or by thicker neck walls, the results could be the same.

    In other words, I have a rifle with a tight neck. A very safe published load is a hot load, in this rifle. You could say that every rifle is different, but I choose to believe that the flat primers are/were (mostly) due to the tight neck.

    Good hunting. LB