Partial neck sizing question

Discussion in 'Reloading' started by newmexkid, Oct 6, 2011.

  1. newmexkid

    newmexkid Well-Known Member

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    Does partial neck sizing in anyway affect load pressures? I understand what partial neck sizing does, just wondering about pressures.
     
  2. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Yes, definately. Can cause major spikes in blood pressure when you stick a cartridge haflway in the chamber that won't let you close the bolt, and doesn't want to be extracted, usually at the worst imaginable time. :D
     
  3. twiedenh

    twiedenh Well-Known Member

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    Ha, that makes my blood pressure go up in the backyard nevermind a very inconvenient time.
     
  4. Mikecr

    Mikecr Well-Known Member

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    FL sizing the neck increases pressure compared to partial neck sizing.
    It doesn't affect pressure much, but enough to affect tune.
     
  5. newmexkid

    newmexkid Well-Known Member

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    Please accept my apology. I should have been a little clearer. I partially neck-sized some cases with a bushing die, that were shot in one rifle. Also, I assembled 3 dummy rounds and cycled them through with no problem at all. I was just lost as to whether or not the partial sizing would mess with my pressures.
     
  6. Mikecr

    Mikecr Well-Known Member

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    Nobody could predict exactly where pressure would go, as we couldn't know whether your new bullet grip is higher or lower without specific measurements.
    But your pressure difference wouldn't be any kind of safety issue.

    I wouldn't worry about it. Brass from another gun will have a larger affect until it's fireformed anyway.
     
  7. Kevin Thomas

    Kevin Thomas Well-Known Member

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    newmexkid,

    No apologies needed, and I was just having some fun with it anyway. No, the pressure changes from this single factor alone shouldn't be anything to worry about. You mention using partially sized cases in two different rifles, though, and I can assure that's going to cause trouble down the road. Probably exactly the sort I was joking about. Please, if you're loading ammunition that will be used in multiple guns, always go to a complete F/L sizing. No neck sizing, no partial sizing. Full length size and be done with it. Even at that, you need to understand that conventional F/L dies don't size cases back to their original unfired dimensions, and you can still run into chambering problems if the ammo is used indiscriminately in several different rifles. Keeping the ammo segregated, by gun, is the best way to go. Not always possible, but it's the ideal solution. I myself load many thousands of rounds of match ammo every year that has to work in any of my Service Rifles. No possible way I can segregate them, since they may wind up beind used in either my primary rifle or one of the back up guns, and they have to function flawlessly in all.
     
  8. boomtube

    boomtube Well-Known Member

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    Few of us will ever see any difference between 'full' and 'partial' neck sizing. And there is no benefit to neck sizing below the heel of a seated bullet.