Who has used the RCBS neck sizing dies to bump shoulders on 7mm rem mag?

Discussion in 'Reloading' started by Darcey, Aug 28, 2011.

  1. Darcey

    Darcey Active Member

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    I want to just neck size and bump the shoulders on my 7mm rem mag brass so I can get the best life and accuracy from my brass. Will the RCBS neck sizing die with the bushing do what I am looking for?
     
  2. MagnumManiac

    MagnumManiac Well-Known Member

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    No! A neck die will only resize the neck, no matter how you set it up!

    You need to get yourself a 'body die' from Redding if you want to just 'bump' the shoulder. You will also need some sort of measuring device to measure 'before and after' to get the correct amount of 'bump'.
    The RCBS 'precision mic' is perfect for this. That's what I have always used.
    gun)
     

  3. Darcey

    Darcey Active Member

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    I have been using lee dies but they don't just neck size or bump. So if i neck size and do the bump when needed how often do I full length size or do I have to at all? Sure appreciate the advice.
     
  4. BountyHunter

    BountyHunter Writers Guild

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    The redding body die lives up to its nane. It bumps the shoulder AND sizes the body.

    So body die and NS die is FL sizing! More than one here does not get that

    BH
     
  5. Gene

    Gene Well-Known Member

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    Again, you cannot use a neck size only die to bump the shoulder. The Redding body die, or any F/L die, is what you need. When chambering a round, if the bolt goes down with a great deal of effort, it means the shoulder has expanded excessively, and its time to bump it back a tiny bit, usually .001" or .002" is enough. You need a caliper and devise to fit over half the shoulder to measure how far down you are bumping. You can find these in the Sinclair catalog. Turn the die down about 1/32" at a time, measure, and try in your rifle. Keep doing this until bolt closes with just a very slight resistance. If bolt flops down, you pushed the shoulder back too far. This creates excessive headspace. I throw those cases away. Many will shoot them to move the shoulder out again, but that is risky.
     
  6. Darcey

    Darcey Active Member

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    OK. So with my lee full length sizing die, am i over working the brass by using it? I keep hearing to just neck size until it is hard to chamber then just bump the shoulder back. Is this the way i should go to not over work my brass? And I should neck size before bumping then trim brass length? Correct? Just want to do it right.
     
  7. Gene

    Gene Well-Known Member

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    You can do it either way. Only negative to full length sizing, is that it works the brass excessively, which means you need to replace it more often. If loading for a hunting rifle, I always F/L size, because you want each round to chamber smoothly. Many benchrest shooters F/L resize all the time.

    I always trim about .10" below SAMMI after sizing.