"scoring?" on 308 brass after sizing?

Discussion in 'Reloading' started by JAnderson94, Oct 30, 2013.

  1. JAnderson94

    JAnderson94 Member

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    I was reading here on the net that some people use a FL die as a partial neck sizing die. This is a new caliber for me to reload and have only did a little bit of .223 before this. So I thought this might increase case life, be easier on the brass, etc.

    It is just a RCBS FL die, I'm using Lapua brass. I put a small amount of black sharpie on the shoulder to determine if the case was contacting the die. Then ran the case up into the die with no lube, backed it off and it looked "scored" after it came out with a distinct line where it stopped sizing. I tried with a small amount of lube and it was a little better, but not much. This has never happened with my .223 RCBS die.

    This didn't happen with my Federal brass, but then again it's not known for being a quality brass that the Lapua is...

    If anyone has a tip or idea... it would be much appreciated!


    thanks,
    James
     
  2. Gunpoor

    Gunpoor Well-Known Member

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    I have tried partial neck sizing with a FL sizing die and I couldn't get the neck to size much at all before the shoulder was starting to be set back. First thing though, are you sure you need to neck size only. The only time that I found I really needed to neck size was with a custom built on an FN Mauser action and shilen barrel chambered in 264Win. That chamber was so oversized that I had to neck size to get any case life. IMO, if you want to neck size go buy a neck sizer die and do it right. Also with the NSD you don't need to lube at all.
     

  3. AZShooter

    AZShooter Well-Known Member

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    I believe your scoring was due to your: " Then ran the case up into the die with no lube"
    It doesn't take much to begin scraping off a few bits of brass which sticks to the sizer die walls. Once this happens the scoring will be on every case till you clean up the inside of the die.

    Putting a dry case into the die is a mistake. Subsequent cases sent into die will remove all remants of lube and then you will have a case stuck in the die! It happened to me when I first started loading and you can believe I paid attention to details to prevent that from happening again! It is a real pain to remove.

    Proper sizing with the die you are using IS partial FL sizing. It will extend brass life and is the proper way to resize brass.

    I always wondered why RCBS would have the following instructions for their FL dies:

    "Screw the sizer die into the press until the die touches the shell holder when the shell holder is brought up to the top of the press stroke. Be sure all play is removed from the press leverage system. To do this, adjust the die as above, lower the shell holder and set the die 1/8 to ¼ turn further down so that the press cams over center. Set the large lock nut and you are ready to size. "

    This is very wrong unless you have a very tight headspaced chamber. To do so will work the brass and will cause excessive stretching of the case requiring more frequent trimming and more importantly eventually cause case head separation.

    The proper approach is to size enough so the shoulder/body taper is slightly reduced to fit the chamber with little or no bolt closure resistance. This is what we reloaders call partial full length sizing. You can size less so there is some resistance it is up to you. Personally I prefer no resistance especially with a hunting rifle.

    If you want to neck size only, get a good bushing die that only sizes the necks. You can get away with no body/shoulder sizing for a few firings then the brass will get too tight and you will have to partial resize the brass anyway.

    Unfortunately not every instructional section in a Loading manual or instructions that come with the dies explain how to use the dies properly. Hope this helps. I like to help beginners as do others that post here. If you have more detailed questions all you have to do is ask.

    Ross
     
  4. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    +1 on AZ's comments

    Set up your dies for a couple of thousandths shoulder bump and don't bother with neck sizing only for a hunting rifle- varminters can neck size a couple of cycles then fl when the brass gets hard to chamber. Use good lube- I shy away from sprays and use lube/pad (rcbs).
     
  5. AZShooter

    AZShooter Well-Known Member

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    Thanks for the +1 Lefty.

    I tend to write a bit on the lengthy side and hope it is useful. I can't help but try and get every detail. I am a retired vocational teacher and details were my life as an automotive teacher. My wife says I can't see the forest for the trees. I say I see the forest, the trees, the bark, the cambium layer, the sapwood, heartwood etc.....
     
  6. JAnderson94

    JAnderson94 Member

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    Thank you for the info guys! The detail was really good. I think the die did get brass in it as the scoring diminished as I did more shells (with lube of course!)

    So to measure shoulder bump back does a person use a caliper, micrometer, or??? And should I only do that every 2-4 firing and neck size the rest of the time until there gets to be a small amount of pressure on the bolt handle or partial FL resize every time?
     
  7. varmintH8R

    varmintH8R Well-Known Member

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    I bump shoulders 2thou every time I reload, as I don't like the idea of doing something different every "x" time I reload. Also, as per AZ's point it gives you some tolerance on a hunting rifle (you go to jack round #2 in for a follow up shot and the bolt won't close = major bummer).

    As far as measuring bump, research and buy a headspace gauge kit. Typically they clamp on to your caliper and give you a reading to a datum point on the shoulder. I have a Hornady kit, it isn't NASA type equipment but it gets the job done. I think Sinclair makes one too.

    Measure a fired case, and adjust your die down SLOWLY until you get a measurement 2 thou below that. Then you are set up. Just that easy.
     
  8. boomtube

    boomtube Well-Known Member

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    There's enough variation in dies, shell holders, brass spring back and chambers that all any die instructions can do, or hope to do, is allow noobs to make ammo that will chamber and fire. Passed that, it's up to the user to understand what he's doing and adjust the dies for best effect.

    It's possible but rare to be able to neck size in an FL die, that's why neck sizers are sold. Using any conventional sizer without lube is a mistake because of brass galling onto the die. We can't use enough lube in a neck die to cause any problems. Neck sizing rerely makes much difference in accuracy. Or case life, because most cases fail due to neck splits anyway.

    I hate the loosely tossed around term of "partial" FL sizing; it means nothing. If a case is sized to properly fit it's chamber it's fully resized. It's "partial" sizing only in that the cases aren't fully jammed into the die as far as possible and that's usually over resized.

    You can "measure" shoulder set back in your bolt rifle the old way, adjusting the sizer down in small changes enough to permit the bolt to smoothly close on empty cases and no more. Small die changes mean just that, a few degrees at a time. The oft suggested "small'" quarter die turn is massive, that will move a die about 16 thou, being nearly 3 times more than the normal min:max bottle neck shoulder tolerence of about 6 thou.

    There are several precision shoulder gages helpful for setting sizer dies but perhaps the "best", over all, is the modest priced Hornady "Case Headspace" device that clamps on the jaws of your dial caliper. (It also accepts accessory tools that allow it to measure seated bullet depth on the loaded cartridge's ogive.)