Neck Sizing Issues

Discussion in 'Reloading' started by bowhunthard, Dec 10, 2008.


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  1. bowhunthard

    bowhunthard Well-Known Member

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    Hello all,

    I was wondering if neck-sizing really does offer an accuracy advantage? I have a single shot 22-250 Rem 12LRPV so the magazine issues would not be a problem. I full-length resize now with Hornady New Dimension dies.

    Also if I do neck-size the brass, how to I deal with the "doughnut" of brass that will build up at the base of the neck? And what kind of life can I expect from the cases.

    Should buying a custom full-length resizing die for that rifle be an option?

    Thanks.gun)
     
    Last edited: Dec 10, 2008
  2. Savagebien

    Savagebien Well-Known Member

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    i'd recommend the lee collet neck sizer die, i use one one my .243 win, and i have the hornady new dimension die set which is great, but now i just neck size my brass. i can just neck size about 8-10 times b4 i ditch brass b/c of primer pockets, and i use rem brass. the collet die from Lee is SWEEET! u mentioned it building up a doughnut on the neck, if it happend on my brass i never noticed in accuracy or visually, but my brass gets dirty after lots of firings. also i didn't notice a difference in accuracy in my rifle when i stopped FL sizing every time and just went to neck sizing.
     
  3. boomtube

    boomtube Well-Known Member

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    The question of accuracy vs. neck sizing is just that, a question. It can only be answered by experimentation in YOUR rifle!

    IF a case is FL sized correctly, NS frequently adds no accuracy benefit for factory sporters but the brass may last a little bit longer.

    You can't do better than the Lee collet neck sizer but it does have a learning curve, if you aren't willing to take the time and make the effort to learn to use it, get something else. There will be no "doughnut" problem at all. And I seriously doubt you would see any advantage to a more expensive custom die for a factory rifle.

    A set of Foster BR dies, FL and seater, are about the best option you have for max accuracy in our type rifles. Forster's FL sizer has a great expander ball system. No other seater die is better for a factory rifle, most others aren't even close. The micrometer seater head option is nice to use but it really doesn't make the ammo any better. Look at www.sinclairintl.com for them.

    Strickly speaking, a neck "doughnut" is a thicker ring that developes at the neck/shoulder junction when reforming a large case to a smaller one and is hard to remove by neck turning so it requires reaming. It's really not related to neck sizing, as such. The amount of case neck bulge below where a neck die may stop is not thicker so it has no impact on bullet tension or safe release on firing.
     
    Last edited: Dec 10, 2008
  4. Michael Eichele

    Michael Eichele Well-Known Member

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    Most shooters that neck size that have seen dramatic accuruacy improvements missunderstand where the accuracy is coming from. Some, and I emphasize some of the time the bulk of the accuracy improvment seen from NS vs FL sizing comes from the lack of runout caused by NS. When using standard dies and reloading practices, FL sizing tends to cause alot of runout in the cases from the expander ball. When guys neck size with a bushing style neck die, this eliminates that issue and accuracy goes up causing some shooters to think that the fitted case was the sole reason for the improvment.

    I am not going to sit here and tell you that a properly FL sized case in a sloppy chamber is as accurate as one that is NS only, but after a couple of firings, the brass does get hard to chamber and feeding can be an issue. This is why I prefer to use a body die for the body and a neck die for the neck.

    Keep it simple.
     
  5. woods

    woods Well-Known Member

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    Hey bowhunthard

    A case goes through a transition from new until several times fired. Your new 22-250 cases have a certain amount of headspace, or gap between the case shoulder and the chamber shoulder. When you first fire the case it will expand and close that gap about 85%. During the subsequent firings the case will progressively close the gap until somewhere between the 3rd to 5th firing the case shoulder will contact the chamber shoulder and make it hard to chamber. Generally called a crush fit.

    You can continue to neck size in a small caliber like a 22-250 because the force necessary to close the bolt is less than on a larger caliber, less shoulder area in contact with the chamber. The bolt will be harder to close but you will probably have enough leverage to close the bolt anyway.

    Between the firing of new cases until you develop a crush fit then you can neck size only (the first 3 or 4 firings). After you develop a crush fit it is best to push the shoulder back a minimal amount for easier chambering and to prevent a problem in the field.

    Personally, I prefer to use a Lee Collet for sizing the neck and then a Redding Body Die to size the case body and push the shoulder back .001" or so for a slight crush fit. What I call Partial Full Length Resizing but definitions vary.

    Bushing type neck sizers are good pieces of equipment but you need to realize the the bushing sizes the outside of the neck to a specific dimension and pushes all the variations in neck thicknes to the inside of the neck. For that reason they are best used in conjunction with neck turning and without the expander that comes with them. With a consistant neck thickness then you will have less runout with the bushing type dies.

    Do-nuts are only discernible with a tight necked custom chamber. It is possible that all cases develop do-nuts but the only way to tell is if your fired brass has an inside neck diameter after firing that is very close to caliber diameter. You insert a bullet into your fired neck and if it will not go past the neck/shoulder junction, then you have a do-nut. In a factory chamber where the neck clearance is larger than .003" the do-nut will not protrude far enough into the neck to stop the bullet, so it will have no effect anyway. You can not get rid of do-nuts with a die, you have to inside ream or cut them out some way or other. Anyway, if the bullet passes by the neck/shoulder junction in a fired-unsized case then the do-nut (if there is one) will not contact the bullet after sizing, so it is a non-issue.

    I have 4 tight necked rifles and turn for .003" clearance on all of them but only my 280AI develops do-nuts. Don't know why, just the way it is.
     
  6. Marine sniper

    Marine sniper Well-Known Member

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  7. boomtube

    boomtube Well-Known Member

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    "It is possible that all cases develop do-nuts but the only way to tell is if your fired brass has an inside neck diameter after firing that is very close to caliber diameter."

    Wood's point is quite correct and well made.

    I abreviated my comments before and failed to mention that ANY case which stretches when fired will eventually push a part of the thicker shoulder into the neck. It will form a "donut" then, just as case refoming does. I was considering that most reloaders will toss cases before that becomes an issue.

    If we adjust our FL sizers to barely bump the shoulder each time, the cases should chamber easily and stretch the least possible amount. That prevents both donuts and head seperations for quite a few reload cycles.