Pressures, Case Strength and Back Thrust

By ADMIN · Aug 21, 2010 ·
  1. ADMIN

    ADMIN Administrator

    Mar 6, 2008
    This is a thread for discussion of the article, Pressures, Case Strength and Back Thrust, By Bob Jourdan. Here you can ask questions or make comments about the article
  2. jmden

    jmden Well-Known Member

    Nov 2, 2003
    Great read on backthrust/chamber friction related to case dimensions and geometry, Len. Thanks. I was thinking about this 2-3 yrs ago and wondered how dry/clean my chamber and cases were. Started swabbing the chamber with acetone as a last rifle cleaning step to completely clean/dry it out before shooting and giving brass walls a quick wipe as well as a last step before storage in the ammo box. The theory was to create more chamber wall friction and less backthrust...who knows.
  3. royinidaho

    royinidaho Well-Known Member

    Jan 20, 2004
    Good read,

    The image on page two is mislabeled.
  4. fj40mojo

    fj40mojo Well-Known Member

    Jul 25, 2009
    Good read Bill,
    I was excited when I saw this article and your name along with it. I'm very interested in the 6.5x55 BJAI. How does it compare to say the 6.5-284? Would you consider it to be a worth while modification to a 6.5x55 rifle specifically built on a '98 Mauser action. I'm having a great time with my Swede but case life is lacking and I'm considering recutting the chamber to your Ackleyized cartridge.
  5. Bob the nailer

    Bob the nailer Well-Known Member

    Dec 9, 2009
    Great job on the article! always enjoy your work, I built a B.J.A.I. 6.5x55 some years back on a M96 Swede action and never regreted it. Oh yea I picked up a M96 Swede 22br "tight neck" from Bob White ( Built by "Bob Jourdan" you did a fine job machining that one). RL15 and 50 grn noslers are the one hole recipe there, Thanks again for some great articles.

  6. ken snyder

    ken snyder Well-Known Member

    Jul 26, 2010
    Maybe someone has an answer. one of my wildcats is being confusing. I used a .375 R.UM. for the parent brass and made a cartridge that is similar to the .375 Dakota. Its inspiration was to make a longer version of a W.S.M. with .375 diameter bullets. Very little taper and tight headspacing. My concern is that I (QUESTION?) by design eliminated case stretching as one of the common pressure indicators. I honestly do not know if ease of extraction and fired case measurements will begin to show signs of overpressure before a critical loading is reached. -- any ideas?