temp sensitivity of factory loads ?

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  • Drifter
    Chieftain
    • Mar 2011
    • 1662

    temp sensitivity of factory loads ?

    Temperature sensitivity of various powders for reloading is often discussed, but haven't found any discussion regarding factory loads.

    Specifically, I'm curious about temp sensitivity of AA's 123gr Lapua Scenar ammo, and also Hornady's 123gr A-Max.

    Anyone have some knowledge to share?

    Thanks
    Drifter

  • #2
    I shall be at our range early tomorrow temps are looking like 95F w/100% humidity it's going to be gusty with a 25+ headwind so from 50 - 200 yrds with AA123's, home rolled 123's, wolf 120's, some 95 AA's and various other home rolled loads. I will let you know if anything out of the ordaniry happens. I have sent quite a few AA 123's downrange in all temps and they always perform well out to 200, I usually within 1-2" out to 200 at worst under 1" at best. This will be the hottest day I have shoot my grendel as yet.

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    • LR1955
      Super Moderator
      • Mar 2011
      • 3355

      #3
      Drifter:

      Easy for you to test.

      Get an cooler filled with some ice, a camp stove to boil water or some MRE Heaters, a ten dollar indoor outdoor thermometer from Radio Shack, your chronograph, and go for it.

      I have done this with issued ammunition as part of a demonstration of ammunition temperature. Nothing dramatic but pressures did go up and performance dropped with ammunition that was over about 120 degrees F.

      It didn't drop as much with ammunition at temps down to about 40 as you would think given the crap on the internet. Dry ice can probably get them cooler but I only had ice.

      So, performance in terms of accuracy will drop at either extreme and pressures certainly will go up when the ammunition temp is hovering around 110 or 120.

      Now, if your ammo is 70 and the outside temp is extreme, you will not have any issues at all in the internal ballistics arena unless the metal of the rifle or its function has been altered due to the extremes of temperature. You will have issues at longer ranges (300 plus) but it must be very extreme before it will matter for most target sizes.

      In the summer time, keep the ammo protected from the sun is my advice. Easy to do with magazine pouches. In the winter, it is up to you whether to keep the ammo in a bandoleer inside a layer or just shoot it at ambient temperature.

      US military powder is pretty robust when it comes to temperature changes compared to commercial powders IMHO.

      LR55

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      • bwaites
        Moderator
        • Mar 2011
        • 4445

        #4
        Both AA and Hornady are using powders not available to hand loaders which are more temp stable than most we can get. A few of the new Extreme powders, like XBR 8208 are comparable.

        Comment

        • Drifter
          Chieftain
          • Mar 2011
          • 1662

          #5
          Originally posted by bwaites View Post
          Both AA and Hornady are using powders not available to hand loaders which are more temp stable than most we can get. A few of the new Extreme powders, like XBR 8208 are comparable.
          That's kinda what I suspected (that factory loads are less temp sensitive versus available reloading powders).

          I also wonder if any of the recently released powders more closely resemble factory offerings. I have a suspicion about one powder / factory load in particular, but it may be far-fetched, and will require additional testing. But I didn't want to chase a duplicate of a factory load if the factory load is also overly temp sensitive.

          Thanks for the replies.
          Drifter

          Comment

          • bwaites
            Moderator
            • Mar 2011
            • 4445

            #6
            Hornady's factory load uses a powder in the Superperformance family, but we aren't aware if it is the same Superperformance powder available to handloaders.

            Leverevolution seems to closely match the factory performance, but I haven't pulled a factory load and compared the two, and the word is that Leverevolution isn't as temp stable as XBR is.

            HMMMM....I have all three at home (factory loads, XBR, and Leverevolution), maybe its time to do a little comparison!

            Comment

            • Variable
              Chieftain
              • Mar 2011
              • 2403

              #7
              Originally posted by bwaites View Post
              Hornady's factory load uses a powder in the Superperformance family, but we aren't aware if it is the same Superperformance powder available to handloaders.

              Leverevolution seems to closely match the factory performance, but I haven't pulled a factory load and compared the two, and the word is that Leverevolution isn't as temp stable as XBR is.

              HMMMM....I have all three at home (factory loads, XBR, and Leverevolution), maybe its time to do a little comparison!
              Yep, so get cracking!!! We'll be waiting for your results!
              Life member NRA, SAF, GOA, WVSRPA (and VFW). Also member WVCDL. Join NOW!!!!!
              We either hang together on this, or we'll certainly HANG separately.....

              Comment

              • Drifter
                Chieftain
                • Mar 2011
                • 1662

                #8
                Originally posted by bwaites View Post
                Hornady's factory load uses a powder in the Superperformance family, but we aren't aware if it is the same Superperformance powder available to handloaders.

                Leverevolution seems to closely match the factory performance, but I haven't pulled a factory load and compared the two, and the word is that Leverevolution isn't as temp stable as XBR is.

                HMMMM....I have all three at home (factory loads, XBR, and Leverevolution), maybe its time to do a little comparison!
                Maybe you're on to something. But I'm leaning in a little different direction.

                Stay tuned...
                Drifter

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