.20 cals - 20x47L & 20 250 improved load testing

Discussion in 'Reloading' started by mghoodlum, Oct 30, 2011.

  1. mghoodlum

    mghoodlum Member

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    I've been testing two new 20 cal magnum I plan to use for coyote hunting.
    I started off with 20x47L and RL-17.
    The loads maxed out around 42.5 grains at a little over 4200fps.
    Most accurate loads were at 41.0 and 41.5 at 4125 to 4150fps.
    I was shooting 38gr unmussig bullets.

    Next I shot some fire form loads in the 20 250 improved with 40 grains of 748 and 39 grain Sierra's.
    Pressure was a bit high on these but not excessive. The real surprise was the velocity! These were humming along at 4500fps. Unfortunately most of the bullets didn't make it to the target.

    I forgot to mention that both barrels are 1:12 twist.

    I'm thinking I need to try the 748 in the Lapua as well. I thought it was going to be a bit fast for these case capacities and bullet weights but it may be just the ticket and I have about 16 pounds of it. More than enough to burn up both barrels.

    I purchased both of these while waiting on my 20 chupacobra that is being built. It's based on a 22 250 improved with the addition of the shoulder moved forward as well. After today's testing I'm thinking I may be able to get about 4700fps with the Chupacobra and the Unmussig bullets.

    Lessons learned:
    W748 may be a great powder for this capacity and bullet weight.
    39g Sierra's will not withstand 4500fps
    Back off fire form loads to 38 or 39g.
     
  2. strombeckj

    strombeckj Well-Known Member

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  3. mghoodlum

    mghoodlum Member

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    No such website exist and since I purchased this rifle here I figured this was just as good of a place as any for the post. By the way I believe the website you are referring to is Saubier.com.
     
  4. steelshooter

    steelshooter Well-Known Member

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    They are interesting results. I was only thinking recently that I may have been better off going with a 20x47 instead of the 20br, due to its feeding problem. I just wasn't sure if it had even been done before. Perhaps when I burn the throat out and it needs re-chambering I might look further into it, however its only just been built and I've just bought all the loading gear for it (dammit!).
     
  5. mghoodlum

    mghoodlum Member

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    I'm really curious how long barrels will last myself but with 3 guns I should be in business.
     
  6. mghoodlum

    mghoodlum Member

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    Jon... By the way I joined that forum a while back but was never granted posting rights as I remembered that after your post and realized that I could not post. So if you know someone over there who can fix that let me know.