30-378 200 grn Accubond Load

Discussion in 'Reloading' started by SquirrelNuts, Nov 5, 2008.

  1. SquirrelNuts

    SquirrelNuts Active Member

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    Dec 12, 2007
    Could anyone give me a place to start with this load?

    I've been shooting 180 grain Accubonds with 111 grn Retumbo at 3410fps.

    If I stay with this powder, how many grains should I use?

    Thanks everyone.
     
  2. HoytemanPA

    HoytemanPA Well-Known Member

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    Dec 16, 2001
    My Accumark barrel loved 106.5 Retumbo, FedGM215 primers, under the 200 Accubonds. A load I used to get several long range woodchucks, including one at 1198, and a 660 deer with a few years back.

    I also see in my load notes "109 TOO HOT".

    I would do a ladder from 104 to 108.5 in half grain increments to see if anything stands out.

    Also here is a little test I did with my last 30-378 barrel, just prior to swapping it that I thought might be useful.

    While I usually don't beat on skinny barrels too bad, I had already made up my mind I was going to replace it with a heavy custom. I also intended to have the action trued up, which meant that I wouldn't be able to use the barrel afterward.

    The "testing" so to speak started with the Retumbo load listed above. In one sitting I sat and threw 40-50 of them, learning wind, I paused for different changes I noted with the wind and what it affected, etc. Shots were probably less than a minute apart. It took quite awhile scrubbing but it recovered.

    Then I tried the H50BMG load on a different outing. That test consisted of 25 back to back and got it hot. Again some pretty good scrubbing and all was well.

    Third time I had a decent load with RL25 and 220mk, second and third rounds busted clay birds (after an angle and wind correction found with the first) at 1K. So some friends and I went for gongs, clays etc. Somewhere shortly after round 20 things went bad in a hurry and 1/2moa went to BIG. No amount of cleaning helped it, and I was aggressive in my attempts to get it clean. There were a couple of major lumps I could feel and never get out of the barrel. Test was done, new barrel went on.

    I have since avoided RL25 in this caliber, but continue to use it for a friends 300 rum I load for, which sees very little use(abuse).

    FWIW,
    HPA
     

  3. SquirrelNuts

    SquirrelNuts Active Member

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    Dec 12, 2007
    So do you think your barrel was shot from using RL25 powder for that gun, or from letting it get HOT?

    I've heard Retumbo is a good powder for the 30-378 since it's a slower burn.

    I am paranoid about waiting for my barrel to cool when I'm on the range.
     
  4. J E Custom

    J E Custom Well-Known Member

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    Jul 29, 2004
    My favorite powder for the 30/378 is H5010 or 50bmg.

    I tried the retumbo and found that it went from mild to very hot with just a few tenth's
    of a grain increase in powder charge.

    With the H 50bmg I can load from 114 to 122 grs and see only slight changes in pressure
    and no extraction problems.

    My 30/378 is a factory chamber spec ( lots of freebore ) but with the 200 gr AB has shot
    a 5 shot 100yrd group of .092 so i'm happy with that .

    J E CUSTOM
     
  5. HoytemanPA

    HoytemanPA Well-Known Member

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    Dec 16, 2001
    SquirrelNuts,
    I think it was the combination of the two. As I am sure that I got it just as hot, if not hotter with the H50BMG test. And I had shot similar amounts of rounds during load development using RL25, but allowed it to cool without adverse affects.

    Intentions of the tests were initially to find the limitations of the powder/heat effect in the expendable barrel before using the round for 1KBR in which a minimum of 12-13 rounds are sent in less than 2 minutes. And while it didn't shoot bad, the greater bag disruption and added expense of components, offset any gain that came from reduced wind deflection.

    So now it is a pretty blue varmint/hunting rifle that I am sure I can send the first 10 where they are supposed to go at any rate of fire. With the factory Accumark I think I would limit rounds to 5 or 6 and allow it to cool.

    My findings mirrored J E Customs with the Accubonds being a very good bullet for normal Weatherby freebore. But I couldn't get them to shoot in my current shorter throated chamber.

    Also agree H50BMG is a good powder for this cartridge, I have 6 pounds left for this barrel.

    Let us know how you make out.
    HPA