Measuring bullet bearing surface?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Dan B, Jun 9, 2006.

  1. Dan B

    Dan B Well-Known Member

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    How is this accomplished? I've heard (read actually) of shooters measuring and sorting bullets according to the bearing surface...and that this makes for a significant improvement in LR accuracy. I have several capable LR rifle that could be tuned up a little better and I'm in the process of having a new LR rig assembled (by the newest member of the 2K club /ubbthreads/images/graemlins/grin.gif)...this would be a good time to see what all is involved in this process, tuned my current gun a little better and see if it is really worth it.

    Thanks......Dan
     
  2. winmagman

    winmagman Well-Known Member

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    The poor mans way would be to buy 2 Stoney Point comparators, put one on each blade of your calipers, drop bullet in between, and measure away.
     

  3. bigrich954rr

    bigrich954rr Well-Known Member

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    ok thats how i do it what is the rich mans way then.
     
  4. winmagman

    winmagman Well-Known Member

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    I read somewhere, escapes me where, that there is a tool specifically for that application. For all I know it might cost less than the 2 SPs /ubbthreads/images/graemlins/grin.gif you might be doing it the rich mans way.
     
  5. edge

    edge Well-Known Member

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    TRUE poor man, would be to size TWO cases tight, and trim to length. then put a bullet into the case, 1 regular and one backward and measure the length of the cases /ubbthreads/images/graemlins/wink.gif

    Probably too cheap, but what the heck!

    edge.
     
  6. Andy W

    Andy W Well-Known Member

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    You just need one Stoney Point comparator. It is the measurement from the ogive to the base of the bullet. Base of the bullet on the blade of the caliper and the top of the bullet in the comparator. Overkill unless you are heavy into the benchrest scene with a br or a ppc.
     
  7. uncleB

    uncleB Well-Known Member

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    [ QUOTE ]
    You just need one Stoney Point comparator. It is the measurement from the ogive to the base of the bullet. Base of the bullet on the blade of the caliper and the top of the bullet in the comparator. Overkill unless you are heavy into the benchrest scene with a br or a ppc.

    [/ QUOTE ]
    I could not disagree more with this statement, measureing from the ogive to the base of a bullet tells you absolutely nothing, it would be like me giving you my phone number 226-_ _ _ _ without the numbers at the end it is meaningless.
    the 2 Stoney Point comparitors works fairly well and is inexpensive. this is what I use for measureing 107gr SMK's etc. for the .338cal 300gr SMK bullet I shoot past 1 mile you need something more precise so I use a bullet bearing surface comparator that has 2 ground bushings for 338cal and a .001" dial indicator. I have a picture of this somewhere but cant find it right now. I got mine from Bill Shehane at D&B Supply in cramerton NC or David Tubb sells the same thing.
    if you are only shooting to 500-600 yards this process may be a waste of time ,if you shoot out to 100yds+ it is something to strongly consider, if you shoot out past 1500yds you are wasting your time if you dont measure bearing surface length IMO
    UB
     
  8. davewilson

    davewilson Well-Known Member

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    measuring from the ogive to the base tells you absolutely nothing? if knowing the beginning and end of the projectile going through the air means nothing,you're missing out on a very important ingredient to consistancy.i'm not saying that bearing surface length is not also,but some think that ogive to base is more important.i sort by doing both and it seems if you sort ogive to base first,the bearing surface length will need very little sorting.
     
  9. uncleB

    uncleB Well-Known Member

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    Dave,
    you talked about " the beginning and the end of the projectile going through the air" but you left out from the ogive to the meplat "a very important ingredient to consistancy" I sort my bullets first by bearing surface length then sort again by measureing from the rear bearing surface to the meplat, by doing both it seems like measureing from base to ogive "will need very little sorting" and mean "absolutely nothing"
    UB
     
  10. uncleB

    uncleB Well-Known Member

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    I found the pic. a stoney point is on the left side of the block and a meplat trimmer on the right [​IMG]
    UB
     
  11. davewilson

    davewilson Well-Known Member

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    UB,i would agree with you on the rear bearing to tip.not sure i understand your "absolutely nothing".if you mean that after sorting with three different processes, the bullets are very consistant and sorting by base to ogive is not neccessary because they are all the same.i also agree,i said this myself.if you mean how far the base sticks out the back doesn't mean much,i disagree.i think the other three are more important, but where the base is in relation to the front still means something.