Sizing confusions

Discussion in 'Reloading Forum (All Calibers)' started by Al Lu, Jun 11, 2019.

  1. Al Lu

    Al Lu Silver $$ Contributor

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    I was under the understanding that Full Sizing Brass is the standard for reloading rifle ammunition? While checking load data on the VihtaVuori site under how to reload rifle ammunition I get this?

    "2. RESIZING THE CASE NECK
    When cartridges are to be used again with the same weapon, resizing only the neck is an adequate procedure. This reduces the strain on the case compared to full resizing. The case neck is resized to its original dimensions with an appropriate collar. Remember lubrication."

    What gives?

    https://www.vihtavuori.com/reloading-data/how-to-reload/
     
  2. Rsadams

    Rsadams

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    Neck sizeing was a stand by for many years , plus the brass lives a long time.... These days people have gone to full length because of the uniformity of the brass.... Plus it insures it will chamber. Full length resizing the minimum , .001 for bolt or .003 for an automatic really helps the brass live a long time... No sense chancing it when it's very important that the round won't chamber.... Other than that it's personal preference.... I have always just full length sized everything....
     
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  3. Sandstorm

    Sandstorm

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    Everyone has there preferred method. I find I get more runout
    sometimes just neck sizing my cases..and have been full lenght sizing mostly now.
     
  4. Straightshooter1

    Straightshooter1 Gold $$ Contributor

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    Full length sizing is best used for several situations, like: cartridges used in rifles exposed to environmental hazards where one needs to have have enough clearances to handle things like dust, grit and grime; cartridges that might be used in various guns of the same caliber; even cartridges used in custom built rifles where tolerances are tight.

    Neck sized cartridges seems to me to work well in factory rifles by maintaining a closer tolerance to the particular rifle chamber, AND. . . it helps prolong the life of the case longer than full length sizing. Neck sizing can have a little more involved in keeping the cartridges reliable as one needs to keep watch on the freebore and having to bump the shoulder ever so often if not every time.

    Since I use a factory rifle, and only use that gun from a bench, I prefer to neck size my cartridges (even do Partial Neck Sizing) to get the best performance I can. I tried and compared full length sizing with my gun, and it just does better with neck sizing . . so that's what I do and why.
     
    Last edited: Jun 11, 2019
  5. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    I dont look to powder mfrs for case sizing advice. Looks like they copied and pasted that from a lee book from the 50’s
     
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  6. Webster

    Webster

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    Don't understand the strain on the case body comment. The case body should never fail. From what I have read you can neck size until the body expands a little to much causing a click sound or slightly difficult extraction. Short range BR shooters always do full length resizing with dies made to fired case dimensions. Standard FL dies almost always reduce the neck way to much.
     
  7. jr600yd

    jr600yd Gold $$ Contributor

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    FL size, you’re gonna have to do it eventually anyway. It’ll save you a lot of headaches.
     
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  8. Bill K

    Bill K Silver $$ Contributor

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    If you only use the brass in the same rifle each time, you would be fine just neck sizing until the case needs trimming or FL size if it begins to fit too tight, which will depend on how hot or mild your loads are.
    But if you use the same brass in more than one rifle in that caliber and want to make sure it always chambers well, then FL size and be happy.
     
  9. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    Problem is, you dont know when too many is too many and you may as well forget your bolt when you go shoot. Neck sizing will bite you eventually and why when its so easy to fl size?
     
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  10. K22

    K22

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    One of the most misunderstood issues in reloading - the neck sizing myth carried over from the 60's and 70's.

    Full length sizing done properly, (i.e. a .001 to .002" shoulder set back - bolt rifles) will NOT reduce case life or adversely affect accuracy. I've loaded thousands of rounds, both ways, and can attest to this without any reservations whatsoever.

    In addition, full sizing will ensure reliable functioning which is critically important at least to me.

    I should qualify this statement by explaining that I dedicate a group of cases to a specific rifle - I do not interchange cases between different rifles. The shoulder set back is based on a fired case from the specific rifle I'm loading for.
     
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  11. Zero333

    Zero333 Silver $$ Contributor

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    Get the Hornady Headspace Comparator kit and use it when full length sizing to determine how far you're bumping the shoulders. I aim for 0.0015" to 0.003".

    There is no magic number how far to bump the shoulders, as long as it's not more than 0.004" and all the cases are the same.
     
  12. Metal God

    Metal God

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    Seems pretty straight forward to me . What part do you not understand ? Is it the fact they did not explain what stain is exerted on a case body that are FL sized ?

    If so , The first question may be what is FL sizing ? At first glance that sounds like a silly question but upon further thought maybe not . Is full length sizing defined by sizing the case body it's "full length" ? Is FL sizing defined by sizing a case to where you get any shoulder set back ( bump ) ? Is FL sizing when your die and standard shell holder make firm contact at the top of the stroke ? All three of those can produce very differently sized cases .

    See there FL sizing is not as easily defined as it appears on paper , just like much of what we do in reloading . So simply saying I FL size does not give the full story as to what you are doing .

    Lets start with the later , making firm contact between the die and shell holder at the top of the stroke . I say firm contact because just screwing your die down to barely kiss the shell holder results n a gap between the die and shell holder when actually sizing the case .

    THIS DIE IS ADJUSTED TO BARELY TOUCH THE SHELL HOLDER AT THE TOP OF THE STROKE WHEN NO CASE IS BEING SIZED . Note no gap between the die and shell holder .
    [​IMG]

    BELOW IS THE SAME DIE SETTING ONLY THIS TIME A CASE IS ACUALLY BEING SIZED . Note the gap that has appeared do to press deflection/flex when a load is introduced on to the press when sizing a case .

    [​IMG]

    Ok that explained , Making "firm contact" between the die and standard shell holder often results in the shoulder being set back more then is needed and creating to much head clearance . When you have to much head clearance when the cartridge is fired the web area of the case stretches because to much strain is exerted on the case body in that area as the head is forced back against the bolt face . If you continue to size the same case in that manner with to much head clearance you will get case head separation or case failure .

    As seen here , these were only reloaded 3 times but had .008+ of head clearance each time . This resulted in the web stretching to much over those three loadings causing these case head separations

    [​IMG]

    In short , that's how case bodies can fail do to stain when FL sizing .

    Hope that helped
    MG
     
    Last edited: Jun 12, 2019
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  13. Richard Coody

    Richard Coody Gold $$ Contributor

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    The shoulder set back is based on a fired case from the specific rifle I'm loading for.

    That is the correct statement. I would just add one caveat to it.

    Biggest mistake i see new reloaders make is setting that shoulder bump on a piece of fired brass that is not fully fireformed yet. When you do this you may think you have set up your die for a..001 shoulder bump and in reality it might be .005 or more. When you do that soon you will see that bright line on the post.above.
     
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  14. Al Lu

    Al Lu Silver $$ Contributor

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    Got it, "don't look to powder mfrs for case sizing advice", Full L Size correctly and stay out of trouble.Thanking the experiences of Accurate Shooters members (note that a bunch of them are contributors). This is another reason why I contribute and will upgrade.
     
  15. K22

    K22

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    I guess that can happen but I haven't experienced it yet and haven't had to adjust the initial die setting for up to 12 to 16 reloads depending of caliber after which I retire the cases. I also haven't had any incipient head separation indications. I do verify shoulder set back (w/ case gauge) every time I load over the life of the case.

    However your point is valid and is something to be aware of. Shoulder set back (die setting) should be verified frequently and not assumed to be constant over the life of a case.
     
  16. Richard Coody

    Richard Coody Gold $$ Contributor

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    Simple question. Do you have a set of headspace gauges. They are quite inexpensive.

    Take a fired case and measure base to shoulder datum and compare that to one of your sized cases and let us know what the difference is.
     
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  17. Pawnee Bill

    Pawnee Bill

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    I neck size with all my bolt guns. Only FL when I have to. Seems to work, been doing it that way for 30+ years. Have yet to have brass problems.
     
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  18. JMayo

    JMayo

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    I FL & neck size with a custom made die with drop in neck sizer bushing.
    Just as easy as neck sizing only I would think. (Idk)
    I want the case & shoulder exactly where they should be.
    I use a PMI tool on my die for setting the die for the correct shoulder bump to the .000
    Older cases require .000 more bump to stay.
    All this is done for my BR rifle.
    If I had an AR I'd hate to deal with non lock ups .... But I doubt I'd be so particular.
    Do what you do. If problems start change.
     
  19. divingin

    divingin Gold $$ Contributor

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    In my experience, continual neck sizing works, until you get a slightly heavier bolt when closing. I have not had a case that wouldn't chamber; they are just tighter when chambering. Those cases I mark (Sharpie on the case head.) Marked cases get run through a Redding body die set to put the shoulder about where the other cases are (or a tad shorter), and then go back into the usual loading routine.

    To be fair, I'm running fairly middle-of-the-road loads pressure-wise; if you're loading towards the hotter end this may not work for you.
     
  20. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    Gotta do what works for you but ill throw this out there- consistency is the end goal. Your cases, if not FL sized to the same dimension every time, have a different capacity right? Then all of the sudden you set it back and start over. Its like annealing every third firing- thats 3 different conditions that brass is in.
     
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