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10mm, how much is too much?

Discussion in '10mm Reloading Forum' started by sglatzel, Jun 30, 2012.

  1. sglatzel


    Apr 4, 2006
    Scottsdale, AZ
    I have been loading for a while, mostly 40cal and 10mm. I started using Unique, very safe loads. Looking to expand what I am doing I moved to Power Pistol, lots of flash and bang compared to Unique. Now for the problem, as I moved up in loads on the 10mm I saw the smiley's, but also got to the point of having the primers blow out. This is a stock G20 gun, I also have a G29. So the bottom line, which is worse blown primers or smiley's? 10mm Power Pistol is loaded at 10grains as the Alliant web site gives for the maximun load. 40 cal is loaded to 9 grains. When I am out of the current loaded ammo I don't think I will load that hot again.
  2. WeeWilly


    Nov 12, 2011

    A smiley or blown primer is too much.

  3. dm1906

    dm1906 Retired SO

    Sep 7, 2010
    PRK (Kalifornia)
    Power Pistol and Unique are fast powders. If you're pushing the pressure, you must move to a MUCH slower powder. They may seem powerful and make big bangs, but if you put them through the chrono, you'll be sorely disappointed. A lot of bang, no buck.

    Smilies are an indicator of excessive pressure. Loose primers are a sign of HUGE excessive pressure, and significant timing issues. They can loosen for one of 2 reasons (assuming the brass and primer was good to start): Brute force pressure during an early unlock; case head expansion, caused by such excessive pressure the pocket opens. Measure your case head and web diameters before and after shooting. If you are losing primers, the case is far out of spec, regardless of the reason. Do not consider reusing that brass, for any reason.
  4. _The_Shadow

    _The_Shadow Ret. Fireman

    Jul 23, 2007
    Southeast, LoUiSiAna
    :wow:You don't want either...

    Bullet makes/types (even of the same weight) different from those for the data can show different results. Without a CHRONY you will only be guessing with performance.

    The dwell time and lockup can differ from one pistol to the next for various, chamber dimensions, age and worn parts, like those of the locking surfaces, recoil springs.

    Also condition of the brass is very important, from new to used, how hard its been pushed, number of times its been shot, sizing equipment used to recondition the casings.
  5. DWARREN123

    DWARREN123 Grumpy Old Guy

    Jan 25, 2008
    Clarksville, Tn.
    Very hot loads. I like Longshot for 40 S&W and IMR 800-X as primary and Longshot second for the 10mm.
    Be careful. :supergrin:
  6. As I read here on GT and elsewhere (not my experience), those 2 powders mentioned in OP's first post are convenient only for lighter target loads. For hot 10mm loads got to get some slower powder. From my own experience I can recommend Vihtavuori 3N38, suitable in 165-212gr bullets range.
  7. SDGlock23

    SDGlock23 Glockoholic

    I've found in the stock G20 bbl I've never got real good speed before some pretty serious case bulging showed up. Most folks use the aftermarket barrels for better case support so they can push it further, but smileys and blow primers are not good.
  8. wkoukios


    Nov 15, 2011
    I have great results with 800-x and NEW Starline brass for my hottest 10mm (woods protection 200gr hardcast). I push it to near 700 ftlbs in my factory barrel without issue but always use my lone wolf 6" for extra safety margin.
    I don't like reused brass for heavy loads, whats the point. Heavy loads are to push the defense against critters to 10mm's max capability. So after testing and development how many do you need to keep proficient? The 10mm can be loaded to moderately above .40 S&W for self defense. This allows fast recovery and awesome power in a perfect compromise.
    You can find great recipes for 800-x on these forums. Good luck!
  9. zippyhuntin


    Dec 16, 2011
    NE Iowa
    What bullet weight are you using? 7th Ed. Hornady book says that 8.6gr is MAX for 155gr bullet in 40S&W.

    As far as not loading that hot again after your current loaded ammo is need to pull those loads apart.