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change in reloading data?

Discussion in '10mm Reloading Forum' started by Mountain10mm, Mar 16, 2010.

  1. Mountain10mm


    Dec 14, 2007
    Has anybody else noticed a change in 10mm loads as listed by powder and bullet manufacturers? I have printouts from two years ago, and copies of load charts that seem to no longer be current.

    I have been shooting a 200gr. Hornady FMJ (Oh, which Hornady no longer makes - thanks Hornady) over 14grs. of #9. Out of a G20, velocities were about 1180. I can no longer find current data to support this load.

    Also, I have charts showing 14.9 grs. (max load) can be used with a 180 grain XTP...again, I can not find a current listing that OK's this load. In fact if you look on the Accurate Powder web site it says the max load for this bullet is 13.5grs. WTF?

    Using #9, my primers look exactly the same as my Buffalo Bore's do after shooting. No smileys on the brass, no black streaks...

    Am I overloading these things?
  2. _The_Shadow

    _The_Shadow Ret. Fireman

    Jul 23, 2007
    Southeast, LoUiSiAna
    Sounds like the corprate lawyers wanting more safety margin to broarden their stance in courts should problems arise. This is with many of the loadings and calibers not just 10mm...
    Last edited: Mar 16, 2010

  3. MinervaDoe


    Jan 26, 2009
    San Jose, CA
    One of my friends has a Sierra manual from the 60s. Some of the loads they have listed are frightening when you consider some of the older guns they might have ended up in. Over the years, they have lawyered down a lot of the loads.

    It's too bad there isn't much data available on why they now publish whimpier loads.
  4. _The_Shadow

    _The_Shadow Ret. Fireman

    Jul 23, 2007
    Southeast, LoUiSiAna
    Just so many variables with the biggest being Brass(different manufacture & new vs. used) can have a big affect on the chamber pressure and performance.

    Bullets(different manufacture, slight differences in diameter, length & weights)can have a big affect on the chamber pressure and performance. The lenght of a Hollow point will be longer than a FMJ. Also Lead Alloy vs. Jacketed vs. Plated vs. Solid Copper styles, guilding of copper is different than lead alloy types.

    Primers(different manufacture, slight differences such as standard/magnum) can have a big affect on the chamber pressure and performance.
  5. MakeMineA10mm

    MakeMineA10mm * * * * Millennium Member Lifetime Member

    Feb 13, 1999
    Central Illinois
    SOUNDS like you're OK. Have you done comparative measurements of the case head expansion with a very accurate micrometer? This is much more definitive than primer appearance or absence of a bulge. This is why I said it SOUNDS like you're OK. Can't really know it, without measuring. I've got a lengthy article over at about how to do this. (I didn't invent it, Ken Waters of Handloader Magazine fame did.)

    As far as watered down loads go, the change in loads from the 1960s to the 1990s (or there-abouts) occurred because of two reasons GENERALLY (there are other less-significant reasons): 1) Changes in burning speed of the powder, and 2) change from Copper Crusher pressure measurement to Piezo-Electric measurement. There's too many details to get into here, but a lot of the loads in the old manuals are definitely unsafe, in spite of guys these days labeling them "The Load"...

    As far as modern load data changing from 1990 to 2010, the biggest reason is lawyers, but there is a secondary reason which may be much more substantive: The powder's source and therefore burn/pressure qualities may have changed. I believe Accurate Arms' powders have changed sources four times since they were introduced in the early-80s. I know they've come from Israel, Czechoslovakia, Florida, and I'm not sure if or where the fourth one was... Part of the changes in load data may be matching up the current load data to the current powder's qualities in terms of pressures. SO, be careful. If you're loading AA#9 from the 90s, using the info from AA load books from the 90s should be perfectly fine. If you switch to a brand new-production jug of AA#9, you may want to back off and work up the load again. You still may get to your original load level, but you may not, or you may even exceed it (lot-to-lot variations being what they are)...