Trying to determine OAL

Discussion in 'Reloading' started by tooele, May 3, 2011.

  1. tooele

    tooele Member

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    Mar 1, 2011
    Having some trouble with getting a length with the 210 berger bullets in a 300 rum. I am getting real consistent measurements with the Hornandy OAL gauge. THe length is too long for the magazine, so have made the max length what will fit in the magazine. So I seated bullets in the cases X 3 at the determined depth. Started cycling the shells. The Bolt was very difficult to close as if I were shoving the bullet into the rifling. So after a tough time getting the shell out, I remeasured and indeed the bullet had been seated deeper into the shell. With a comparator, original OAL with Hornandy was 4.47 repeated 10 times. Shell length to fit the magazine was 4.211. After feeding the bullet and extraction the length was 4.185. Same thing on all three shells. Each bullet after extraction was marked. So what is the problem here is it the Hornandy shell casing compared to a normally sized casing. Have a hard time believing it is my technique as it is very reproducible? Is it the Berger bullet? There is a big discrepency between the Hornandy OAL and what the rifle determined is the actual OAL (4.185).

    Any advise help would be appreciated.
    T
     
  2. sp6x6

    sp6x6 Well-Known Member

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    Dec 8, 2009
    What I have found is that the hornady gauge uses a generic case they send that reading with my shoulder bump gauge in comp. are lot of times .005 to .007 short, which it seems new brass is similar. I think they recommend sending a fired case and this would get you closer, not sure why you are so far off, I now use the sinclair gauge, but you still use your brass, so use fired, or your shoulder bump and take into account.I use magnify glass to look for marks.
     

  3. MSLRHunter

    MSLRHunter Well-Known Member

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    Oct 3, 2009
    So are you saying that with the oal gauge you measured the distance to the lands at 4.47? I don't load for the 300rum but that sounds pretty long compared to my 300winmag. Where did you measure on the bullet, from the tip or ogive?
     
  4. Mikecr

    Mikecr Well-Known Member

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    It's a horrible system...
    You're relying on the fit of a case, which I take is assumed to be zero headspace with every chamber and bolt in the cosmos!

    Go to 'Woods' posts on both pages for description of a better method (R-P Tool)(with pics):
    Reloader's Nest Forum - OAL
    Some folks do this with a dowel or cleaning rod, and do yourself a favor and pick up a Sinclair 'nut' comparator.
    And oh yeah, drop that Stoney point copy in a red Hornady trash can.
     
  5. tooele

    tooele Member

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    Mar 1, 2011
    Solved the problem. Got everything working. Amazing how a day off a little thought and then tackling the problem again solves the problem. THanks for the help.

    T