Bullet seat depth

Discussion in 'Reloading' started by Gone Ballistic, Apr 19, 2011.

  1. Gone Ballistic

    Gone Ballistic Well-Known Member

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    I'm wondering how many of you prefer to seat your bullets off the lands and grooves verses seating your bullets to SAAMI specified overall length? Most rifles' magazines only accommodate SAAMI OAL thereby requiring one to use single shot method when loading over SAAMI lengths specified. Do you get sub MOA groups with SAAMI loaded ammo? Do your groups improve enormously when you load back off you L&G's?
     

  2. boomtube

    boomtube Well-Known Member

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    SAMMI doesn't specify any OAL/seating depths, as such; they only specify a minimum throat/leade length. It's just common sense that magazines will sccept cartridges that will fit in that minimum length chamber.

    Few sporter rifles with SAAMI chambers shoot best when seated at or into the lands.
     

  3. Mikecr

    Mikecr Well-Known Member

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    Just seat bullets where they shoot best from YOUR barrel..
     
  4. Gone Ballistic

    Gone Ballistic Well-Known Member

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    I guess I stated my question somewhat wrong. What I wanted to know was if the SAAMI coal stated in reloading manuals gave as much accuracy to many of you that reload compared to loading back away from your L&G's. I am thinking about probably having my custom retrofitted with a Wyatt 4" magazine to accomodate the longer lengths and wondered if it would be worth the added cost.
     
  5. boomtube

    boomtube Well-Known Member

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    "...the SAAMI coal stated in reloading manuals ..."

    The OAL in most loading manuals have nothing to do with SAAMI, it's just what the book makers used to develop their listed data. And it rarely has anything to do with the accuracy potential.

    Gun makers can cut the throata as long as they wish, the only thing the specs are concerned with are the minimums and that's done so the ammo makers can know what they are working toward. Customs can be cut anyway you and your smith want it. If you're gonna have a custom chamber cut why not ask your 'smith what he would suggest; I would suggest cutting to match the normal minimum specifications.
     
  6. Bart B

    Bart B Well-Known Member

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    Yes, SAAMI lists an OAL spec for cartridges. Check 'em out at their web site below:

    http://www.saami.org/specifications_and_information/publications/download/206.pdf

    Some cartridges' OAL is spec'd maximum and others minimum. Look up yours and check it out

    Oft times, competition folks will seat bullets a few thousandths longer than leade contact so when the round's chambered, the bullet seats back a bit creating the same start resistance for each shot. This works best with light neck tension on the bullet and for single round loading anyway.

    At the other end of the spectrum, US military 7.62mm NATO M1 and M14 rifles reworked properly for competition would shoot good lots of commercial match ammo inside 4 inches at 600 yards. Not too shabby in those huge military spec chambers, brand new cases and bullets jumping near 1/10th inch to the leade.

    As long as there's no more than a couple thousandths bullet runout, jumping a ways to the rifling's no big issue.