Seating depth-powder vs bullet

Discussion in 'Reloading' started by mtelkhntr78, Aug 4, 2011.

  1. mtelkhntr78

    mtelkhntr78 Well-Known Member

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    I was wondering something when it comes to seating depth.

    For example: in my 300wsm I have a decent load worked up with Rl-17 and 168gr Barnes TSX. I have my OAL dialed in for the Barnes as well.
    I want to investigate some other powders with this bullet so can I/ should I use the same seating depth for the Barnes when I use a differnt powder?

    So my basic question is optimum seating depth specific to the "type" of bullet or more so to the type of bullet/powder combination.

    When/if I find another powder I like should I work on finding a "new" optimum seating depth even though I am still using the same bullet?
     
  2. Browninglover1

    Browninglover1 Well-Known Member

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    My limited experience with trying different powders with the same bullet is that usually the sweet spot for the OAL stays the same regardless of powder. However all my loads have at least a .020 jump into the lands.

    I think if your bullet was right into the lands that could make things behave differently. Someone on here with more loading experience might have different experiences, but for the 3 or 4 guns that I've played with, the OAL sweet spot seems to be the same for all powders tested.
     

  3. Greyfox

    Greyfox Well-Known Member

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    In my experience, using the same bullet, if the bullet seating depth for one powder is in the lands or under .010, I have seen changes to a new powder sometimes require a change in seating depth to optimize accuracy. Much less so with seating depths that are further out, .025+. This probably has to do with a particular powder's pressure characteristics which become more influential when that bullet is in or very close to the lands. If you change powder and keep the bullet close to, or in the lands it's a good idea to start with a lower charge when changing powders.
     
  4. Mikecr

    Mikecr Well-Known Member

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    I think much the same as posted.
    If you are off, but very close to the lands, then an adjustment might affect the pressure peak. It might.
    But for me, best seating has held for a given bullet/barrel, through powder changes.
    If you change bullets, it's back to seating tests for sure.
     
  5. boomtube

    boomtube Well-Known Member

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    "..my basic question is optimum seating depth specific to the "type" of bullet or more so to the type of bullet/powder combination."

    It hardly matters what we think or have experienced, if you want to know what YOUR rig needs you will have to test it.