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Overpressure

Discussion in 'Reloading' started by RedHaze, Nov 6, 2010.

  1. RedHaze

    RedHaze Handgunner

    2,397
    8
    Aug 23, 2009
    SE WA
    Working with 357 sig specifically. With a 125 gr hornady HAP bullet, and the HS-6 I have on hand for now. Started out at max minus 10% and worked up to max without issue. Which Lyman has at 9.0 gr. However, the 357 sig loadbook I have lists max at 9.3 gr for the 125's. So I made me a couple at 9.1 gr and 9.2 gr... Here's what I have to show for it.

    Brass case is mine at 9.2 gr.
    Nickel case is Fiocchi Extrema, which feels a bit hotter than my reloads.

    Anybody see anything here that should be raising an eyebrow? To my poorly trained eyes they all look fine and dandy... But thats me, and I haven't been in the reloading scene long.

    Thanks fellas.
     

    Attached Files:

  2. MSgt Dotson

    MSgt Dotson

    3,268
    8
    Sep 30, 2006
    If running mixed brass, I'd observe the lower of the two max charges given; many manuals that give higher charges use a very specific brass, bullet, and primer. If using 'fired several times' brass, I'd stay away from max charges, and, once the brass has been used 6-8 times, toss it entirely.
     


  3. dudel

    dudel

    5,044
    568
    Dec 10, 2008
    Texas Hill Country
    Hard to tell from the pics. What speed did they cross the screens at? That will give you the best indication of pressure (short of a KB of course!).
     
  4. RedHaze

    RedHaze Handgunner

    2,397
    8
    Aug 23, 2009
    SE WA
    I've no chrono unfortunatly. Thats on the wish list, just like a lot of other things...

    Brass is new starline. I certainly wouldn't use mixed brass to try out max loads. I may be foolish but i'm not dumb...
     
  5. WiskyT

    WiskyT Malcontent

    11,682
    1
    Jun 12, 2002
    North Carolina
    9.0 or 9.3, the powder varies that much form lot to lot. 9.0 with one lot could be higher pressure than 9.3 with the next.
     
  6. RedHaze

    RedHaze Handgunner

    2,397
    8
    Aug 23, 2009
    SE WA
    Interesting, i'll be sure to work 'em up with each new batch of powder then.
     
  7. Damon555

    Damon555

    166
    0
    Mar 3, 2009
    Middle Tennessee
    I'd stay away from max by .5 grain or so....as long as the gun functions properly then there is no need to max it out....IMHO.

    The brass in your picture looks fine. The primers aren't close to being flat.....but that's not the only over pressure indication you might get. Those .357 sigs run pretty hot anyway.
     
  8. RedHaze

    RedHaze Handgunner

    2,397
    8
    Aug 23, 2009
    SE WA
    Yeah, I figured on staying at about the halfway point in the data between the different sources.

    To give myself a little discrepancy room with the variables...
     
  9. dudel

    dudel

    5,044
    568
    Dec 10, 2008
    Texas Hill Country
    Good idea. That's why when you find a powder that works well, you get an 8# keg and do a final workup.
     
  10. Kegs

    Kegs Ol 8 fingers ;)

    2,688
    2
    Oct 26, 2009
    Cold side of conus
    The truth is primer flattening is not necessarily a sign of pressure, and overpressure loads won't necessarily show any signs of pressure at all.

    Only way to assess pressure is via a test barrel and related equipment.

    That being said, the brass and primers looks like they are from wimpy loads.

    I wouldn't be concerned.
     
  11. fredj338

    fredj338

    21,708
    922
    Dec 22, 2004
    so.cal.
    I've never seen an "overpressure" load show no pressure signs at all. There is always something to see, but flattened primers is nto a sure indicator. Max varies o much w/ diff published data sources. In the current Speer, you are good to go upto 9.6gr w/ the GDHP or TMJ. The Hogdon site syas 9gr for the XTP. IME, the XTp is a bit "harder" w/ longer bearing surface & can raise pressure a bit. Siff test platforms, conditionins, components, you have to do what you are doing & work them up. If it work sin your gun, that is your max. The rule of "never exceed max" depnds on whos max. Match the components as closely as possibel & go slow. Form those pics I don't see anything that makes me say back off.
     
    Last edited: Nov 7, 2010