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SAAMI chamber pressure specs.

Discussion in 'Caliber Corner' started by Glockbuster, Sep 4, 2010.

  1. Glockbuster


    Likes Received:
    Jun 30, 2005
    Middle America
    There has been much discussion in this and other forums about how major ammo manufacturers have cut down the loads in modern ammunition. In my mind, there is no doubt there is truth to this and a major factor is probably because modern bullet technology allows this or might be even necessary for best bullet performance.
    Others argue that because of liability issues and some "junk" guns out there manufacturers have seen this downsizing of loads fit to protect themselves from lawyers and lawsuits.
    While a mixture of these factors is the best explanation, my doubts remain as to the exact specifications from SAAMI in some cartridges.
    For example, a knowledgeable person in another forum points to SAAMI pressure specs for 38 special +P at 21,500 PSI. However I have checked this and it seems the current specs is 18,500 PSI.

    So what gives here ? old timers are convinced and have proven to some extent that current +P ammo pales in punch when compared to old ammo, be it standard load or +P loads.

    Any comments ? facts ?
  2. Berto

    Berto woo woo

    Likes Received:
    Sep 15, 2003
    A few variables involved;

    The switch of CUP (copper units of pressure) to PSI measurement has reset the standards.

    The designation of +P came well after hotter loads were marketed...for example the 38/44 and Hi Speed versions of .38sp approached .357mag pressures whereas todays +P .38sp is loaded to 18,500PSI as of the latest means of measurement.

    9mm and .38sp are both over a century old at this point, and so are some of the guns that shoot them. Probably one of the reasons these loads in particular have different pressure designations vs newer loads.

    While pressure peak may be an indicator of a round's performance, some of the newest powders can extend the peak longer, enabling better velocities that once thought possible.

  3. freakshow10mm

    freakshow10mm 10mm Advocate

    Likes Received:
    Oct 9, 2003
    Michigan's Upper Peninsula
    SAAMI is a recommendation, nothing more.

    Ammunition companies load to a specific pressure, usually in the top 95% of SAAMI MAP.