New Loads: Powder Charge vs Seating Depth

Discussion in 'Reloading' started by bookworm, Sep 2, 2009.

  1. bookworm

    bookworm Well-Known Member

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    I'm starting to work up a new load for 300 win mag, Hodgdon H-1000 powder and 190gr Berger VLD's.

    In a recent article on this site Eric Stecker gives some advice on seating depth for hunters. He recommends 4 COAL's at 0.010, 0.050, 0.080 and 0.130 off lands.

    Now I assume I should start with finding powder charge first (using OCW method). If this is the case I'm wondering which COAL you would chose to use to find your optimum powder charge?

    I've read that smaller COAL's lead to higher chamber pressures, so should I choose the 0.010 for my OCW loads?

    Is it possible that different seating depths would have different optimal charge weights?

    If anyone has any advice or knows where I can find a good write up on how to balance these two critical parameters, please let me know.
     
  2. cstilt

    cstilt Well-Known Member

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    I'm kinda interested in this as well. I'm currently working up loads using the same article only I'm using accubonds in a 270win. My way was to first work through the seating depths to find a general idea of about where that should be.

    I went with COAL first because I figured if I had a good charge it would probably be above the starting load. So by finding a good depth with low pressure loads I figure i was able to save some wear on the rifle and brass. If I went with powder first I was afraid of the pressure spikes like you mentioned around the closely seated bullets.

    My plan now is that I've got a good seating depth is to work through the charges and find a good one. Then I'll vary the depth a little on each side of what I have found to fine tune it. I'm going to move it by 0.02 instead of the 0.04 like the article says. I've got my fingers crossed.
     
  3. Slopeshunter

    Slopeshunter Well-Known Member

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    It's kind of like which came first the chicken or the egg. Tweak the powder first or the seating depth?

    I hope to read some interesting posts on this thread.

    Cheers.
     
  4. boomtube

    boomtube Well-Known Member

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    "I've read that smaller COAL's lead to higher chamber pressures, so should I choose the 0.010 for my OCW loads? "

    I suspect you read that about handgun loads and are misapplying it to rifles.

    Starting LONG, at, or very near the lands increases start pressure in rifles. Seating deeper, within reason, decreases start pressure.

    Yes, start close, find your charge. Then test seating deeper to tweak the load.
     
  5. bookworm

    bookworm Well-Known Member

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    Yeah I mispoke...I had "small" in my head as I was thinking smaller distance off lands and then misapplied COAL. I meant to say larger COAL.

    Thanks for clarifying.