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Free bore leade

Discussion in 'Handloading and Reloading' started by JohnM, Jun 4, 2012.

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  1. JohnM

    JohnM Member

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    As a general rule, which is kinda stretching it.
    If you got a chamber plus bullet and case that will allow allow it, just how advantageous is it to have the bullet kiss the lands?
    Single shot barrel, no concerns about magazines, etc.
     
  2. Offfhand

    Offfhand Member

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    Talk to benchrest shooters, the ones who actually shoot in registered competition. They are the most precise, accuracy minded reloaders on the planet, and you'll find that many, probably most, of them seat bullets touching the lands or even "hard jammed" into the lands. Last week at the Super Shoot benchrest tournament I had a chance to talk to a guy who holds the new world's record for the 100 yd light varmint five group aggregate. He told me that he seated his bullets so that they "kissed" the lands.
     
  3. gamestalker

    gamestalker member

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    Well, I've been loading for bottle neck cases for a very long time and was taught from the get go by a bench rest shooter to start up to the lands, and step back in .005" increments until you find the sweet spot if necessary. My experience has been when I'm just touching or right at the lands, my groups are tight. In this regard, I've not had to usually do any adjusting back to improve the groups.

    Just be aware that if your going to get up close and personal, start your powder charges on the low end of the data and work up. There is no doubt that pressures will be higher when touching or getting very close to the lands (.005").

    And if your using a FL die get your head space right. Most bullet olgives have a bit of inconsistency, so if you throw in excessive head space into the mix, it only makes for inconsistent free bore with bullets getting pushed into the lands to deep.

    When deciding when you have OAL at the lands, the cartridge should still drop out of the chamber with gravity alone, or you have them too far into the lands. To do this right you have to hand chamber each round to make sure they are not getting jammed into the lands. Even with high quality match bullets, olgive inconsisteny can be as much as +/- .010", which is enough to jam them too far into the lands if you don't allow for such.

    GS
     
  4. blarby

    blarby Member

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    I second this.

    Pretty much everything GS said here is rock solid.

    I would add, however that having a precision mic for testing freebore is a fantastic aid, and it can be used over and over again.

    After obtaining one, I can't believe I got by doing it the Red Green way.... its now going to be mandatory in every rifle caliber I get in the future.
     
  5. JohnM

    JohnM Member

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    I'm at the Red Green stage, but I do back off contact just enough that all rounds fall in with a click.
    All my cases are usually trimmed to about a thou, bullets are the big variation.
     
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