New way to fire form 7.62x39 cases....

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  • New way to fire form 7.62x39 cases....

    Hey guys, first time to the forum since the crash, had to re-register and everything.

    Anyway, got tired of burning up expensive powder and bullets, wearing the barrel, etc. just to fireform cases. I setup a CNC lathe and turned a pile of delrin bullets that are about the size of 100 grain bullets. They have a slight boat tail, mainly for ease of loading as I could care less how they fly. They weigh 13 grains.

    Used Quickload as a rough guide and ended up with a load of 8 grains of IMR Trailboss and a OAL of 2.170.

    I was able to fireform a bunch of Privi brass today without a range, without barrel wear, and with a very minimum component cost. Just put the muzzle into an old pillow on the back porch and fired away. The action does not cycle, the brass does not eject.

    Cases are fully formed, checked with a mic all along the body. Only difference I can tell from the "real" fire formed ones is that the shoulder isn't as crisp, little more radiused. I am going to order a bunch more material tomorrow and do a big run of these, they are really handy!

  • #2
    can you reuse the "bullets"?

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    • #3
      If you want to do away with the bullets entirely and get a perfect formed case, Mike Milli from Dtech recommends charging your cases with a small amount of fast pistol powder, topping it off with Cream of Wheat or Grits and using the filled case as a punch through a styrofoam cup to keep the contents in place. Discharge in a safe direction. Here's his picture of fire forming 25 WSSM into .358 WSSM:



      Hoot

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      • Longshot_34

        #4
        Hoot-how much is a small amount of powder? 5 maybe 10 grains?

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        • #5
          Originally posted by Longshot_34 View Post
          Hoot-how much is a small amount of powder? 5 maybe 10 grains?
          I seem to recall that somewhere he said 9 grains of Universal or Unique. Whatever you have the most of, or some old stuff to get rid of. When I was fireforming .25 WSSM into .300 WSSM, I also cut small disks of toilet paper and placed one down in the case with a tweezer over the powder, before adding the grits. Probably not necessary as long as you don't disturb the mix before discharging it any more than absolutely necessary. Needless to say, you ease the the bolt closed to chamber each round with it pointing up in the air. If you have a gas limiting block, you want to shut it off to keep the stuff out of the gas system. Otherwise, rotate the gas block to seal off the port in the barrel until you're done.

          Hoot

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          • #6
            I remember the old QuakerOats or Puff being shot from guns. Hey, you are onto something new!!
            As serious as you are, I can't help but laugh a little.

            Steel89

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            • txgunner00
              Chieftain
              • Mar 2011
              • 2070

              #7
              Originally posted by Longshot_34 View Post
              Hoot-how much is a small amount of powder? 5 maybe 10 grains?
              I have used Universal for the cream of wheat fire forming method. Winchester brass took 11.5 gr to fully form and IMI took 13 gr. (harder brass).
              NRA life, GOA life, SAF, and TSRA

              "I ask, Sir, what is the militia? It is the whole people, except for a few public officials. To disarm the people is the best and most effectual way to enslave them."

              George Mason, co-author, 2nd Amendment.

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