Barrel length and powder burn rates?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by bookworm, May 29, 2009.

  1. bookworm

    bookworm Well-Known Member

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    I will be reloading 300WM with H-1000 and 190gr bullet. Application is long range big game hunting. I'm currently shooting a 26" barrel but am considering going shorter...maybe down to 22".

    However, I've read that with slower burning powder and heavier bullets you need to make sure your barrel is long enough to get complete combustion.

    With the combination above and a 22" barrel am I at risk of incomplete combustion? Any advice on what length would be okay?

    Thanks.
     
  2. AJ Peacock

    AJ Peacock Well-Known Member

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    H-1000 is going to be way too slow for a 22" barrel. It's actually a bit slow for the 190 in a 300WM unless you have a super long barrel 30"+ and are loading compressed loads.

    I haven't loaded for a short barrelled 300WM, but according to Quickload, a max load of H4350 will be 100% burnt in a 20.5" barrel behind a 190gr bullet. 22" barrel should work fine with h4350. Should be able to get around 2900fps with it.

    AJ
     

  3. J E Custom

    J E Custom Well-Known Member

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    24'' barrel would be the minimum length in a 300 WM with any powder.

    With a 22" barrel and H 1000 you will lose 100 to 150 ft/sec and gain a giant muzzle
    flash. (Powder burning out side of the barrel),

    I used to shoot a 300WM and it liked around 70 grs of H-4831 .

    H 1000 appears to be at it's best at around 100grs of case capacity.

    J E CUSTOM
     
  4. RT2506

    RT2506 Well-Known Member

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    Keep the 26" barrel. If you go down to a 22" might as well go to the 30-06 while you are at it. Less powder for the same velocity.
     
  5. bookworm

    bookworm Well-Known Member

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    Thanks for the replies fellas.

    AJ, I'm surprised to hear you say that H-1000 is too slow for 300 WM unless you have a very long barrel. The Hodgdon site lists 300 WM as a caliber for H-1000 on their site. There are also recipes and good results in the chat forums with this combination (althought barrel length was not discussed).

    Having said all that, I have not cracked open the keg of the H-1000 yet, so maybe I should consider selling it and going with something slightly faster.

    I originally had my eyes on the H4831.
     
  6. AJ Peacock

    AJ Peacock Well-Known Member

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    H1000 will work with the 300WM, but not in short barrels or light bullets. 4831 is better for 300WM (especially for 180gr and up). But for lighter bullets and super short barrels (as you mentioned in your initial post), I'd use a faster powder. H-4831 will work and may work well, I think you'll get a little better velocity from your short barrel with H4350 though.

    AJ
     
  7. bookworm

    bookworm Well-Known Member

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    Here is a bit of info from Hodgdon on the Chuck Hawks site:

    .300 Win. Mag.

    I know this is straying off topic a bit, but still related...Any thoughts on what a "reasonable" chamber pressure is for the 300WM rem 700?
     
  8. bookworm

    bookworm Well-Known Member

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    Thanks AJ.

    It's looking like I need to choose whether to stay with H-1000 and keep the 26" barrel or go shorter and get a different powder (maybe H4350 as you suggest).

    The idea of shortening my barrel was to make it a bit more packable while hunting but also I've read that it will stiffen the barrel a bit and could improve accuracy. I know the downside is loss of some velocity, but I thought it may be worth it to gain some precision. It's a factory barrel.
     
  9. AJ Peacock

    AJ Peacock Well-Known Member

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    62,366psi is the current standard max pressure for the 300 Win Mag. I know that guys run it in the high 60's in some rifles though.

    I believe that 54000CUP is the old standard CUP for the 300WM.


    AJ
     
  10. nddodd

    nddodd Well-Known Member

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    Hey, this may not help at all but I reload for a buddy of mine. He has a 300 win mag in sf2 and I load 82 gr. of h-1000 behind a 168 smk not the hottest load but shoots ragged holes at 100yds. Haven't had a chance to stretch it out yet been too wet here to get out in the fields.

    Nathan
     
  11. bookworm

    bookworm Well-Known Member

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    Hi Nathan - actually it is helpful to me.

    Do you happen to know the barrel length of your buddies rifle?
     
  12. su37

    su37 Well-Known Member

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    Either slow powder or fast powder , all powders burn within the first 2" of the barrel.

    Longer barrel provide a longer pressure time for either powders.

    Slow powders work just fine in a shorter barrel.
     
  13. AJ Peacock

    AJ Peacock Well-Known Member

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    Absolutely not true, if they burned in the first 2", then why would you see fire out the end of a 20" barrel with slow powder?

    Or find powder granules unburnt when using too light a bullet in too short a barrel with too slow of a powder?

    Quickload does a great job of showing how much powder is burned and at when during the bullet's travel.


    AJ
     
    Last edited: May 31, 2009
  14. su37

    su37 Well-Known Member

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    "Absolutely not true, if they burned in the first 2", then why would you see fire out the end of a 20" barrel with slow powder?"

    Your seeing gases re-ignite when they leave the barrel and hit oxygen.


    ALL POWDERS BURN WITHIN THE FIRST TWO INCHES OF BARREL LENGTH AND NO MORE!

    If you think that slow powders burn all the way down a long barrel you are mistaken.

    Quick Load shows us slow powders that create a different pressure curve than faster powders.

    Longer barrels create longer pressure times.