Barrel length for slow buring powder

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Greg Duerr, Apr 26, 2013.

  1. Greg Duerr

    Greg Duerr Well-Known Member

    Messages:
    1,012
    Joined:
    Mar 25, 2011
    Another question........................When shooting slow burning powder in the .243 AI is a 24inch barrel long enough for powders like RL 22 or even RL 25 or H1000

    Guy are asking me questions that I dont have answeres for..........the reason I ask so many on this sight, I have a lot to learn.

    Greg
     
  2. Mikecr

    Mikecr Well-Known Member

    Messages:
    4,264
    Joined:
    Aug 10, 2003
    Is the barrel long enough for what?

    Same or higher velocity from more slower powder?
    Accuracy that doesn't degrade from excess muzzle pressures?

    It starts with a bullet, it's weight and twist requirements, and case capacity needed combined with given powders to drive the bullet to needed MVs.
    While shorter barrels are stiffer -all else equal, internal ballistics is still a dominant contributor to result.
    While I couldn't prove it, I'm sure there are better barrel lengths than others for each internal ballistic combination and application.
    But it would be a massive undertaking to produce a formula that passes all tests. We won't see it in our lifetimes.

    In otherwords,, try it & see
     

  3. Greg Duerr

    Greg Duerr Well-Known Member

    Messages:
    1,012
    Joined:
    Mar 25, 2011
    Long enough for that slow of powder?
     
  4. Engineering101

    Engineering101 Well-Known Member

    Messages:
    1,010
    Joined:
    Jan 29, 2013
    Greg,

    When you pull the trigger the bullet will go out of the barrel so a 24” barrel is “long enough”. All the powder may not burn but usually when you use a powder that is “too slow” there is a tendancy for the ES to tighten up. I’ve used IMR7828SSC in a 22-250 with good results and that powder is WAY too slow for that chambering.
     
  5. Edd

    Edd Well-Known Member

    Messages:
    2,395
    Joined:
    Jan 26, 2011
    The length of your barrel doesn't change your powder choice.
     
  6. Bart B

    Bart B Well-Known Member

    Messages:
    2,483
    Joined:
    Dec 25, 2005
    It does if you want your load's pressure curve to be the same size and shape for every shot fired. That's a big help for best accuracy and lowest muzzle velocity spreads.
     
  7. MontanaRifleman

    MontanaRifleman Well-Known Member

    Messages:
    6,068
    Joined:
    May 21, 2008
    For shorter barrels I would use faster powders, i.e., H1000 over Retumbo. That doesn't mean the slower powder won't work, but the faster powder will be more efficient and probably more consistent.
     
  8. Greyfox

    Greyfox Well-Known Member

    Messages:
    3,708
    Joined:
    Jan 21, 2008
    I have found no rule of thumb for this. My 24" 300WM gives the best ES (5-10), with 100 FPS greater velocity with slow burning Retumbo when compared to faster burning H1000 or H4831sc. Same holds true with my 6.5x284's in 24 and 26" barrels.
     
  9. Greg Duerr

    Greg Duerr Well-Known Member

    Messages:
    1,012
    Joined:
    Mar 25, 2011
    Thanks that all makes sence...............................
     
  10. lever-hed

    lever-hed Well-Known Member

    Messages:
    248
    Joined:
    May 8, 2008
    There is no direct relationship between bbl length and powder burn rate. Just because someone says well that short of bbl won't shoot well with that slow burning powder is misinformation. Certain powder selections work best based on caliber & bullet, not bbl length. Use whatever suggestions are found in your reloading manual for your specific bullet and caliber. Then go out and find what shoots best.
    THE END.