Fire forming 7.62X39 ?????????

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  • VASCAR2
    Chieftain
    • Mar 2011
    • 6218

    Fire forming 7.62X39 ?????????

    A buddy gave me some brass 7.62 X 39 mostly mixed case, FC IMI, CBC ect. There was a thread on how to do this on AR15.com but its been long enough ago that it is no longer available to me. I was going to tumble the brass then re-size the brass with my Hornady 6.5 Grendel dies. I know I should reduce my powder charge and I figure I'll use the cheapest bullets I can find. I would assume there shouldn't be any trouble getting the 7.52X39 brass to enter the 6.5 G sizing die. I normally ream the flash hole and remove the crimp for the primer pocket. From looking at these cases I didn't notice any crimped primers. Is it normal for 7.62 X 39 to have crimped primers? Do most 7.62X39 use large rifle primers or do they use large and small primers? I've never loaded 7.62 X 39 so any insight would be appreciated. Thanks in advance!

  • #2
    I'd be kind of interested in that myself. I have a bag of boxer primed brass a fellow gave me. Do the necks get too thick after down sizing and need turning? I'm not set up for neck turning though I have an RCBS Trim Pro. Any pet fire forming loads using Unique and Cream of Wheat?

    Hoot

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    • longdayjake

      #3
      Usually brass cased 7.62x39 is not military issue and therefor it isn't crimped. Most of the stuff that foreign militaries use is steel cased berdan primed. IMI would only be crimped if it was loaded for some military. If being shipped to the US it most likely wouldn't be used in military weapons and therefor no need to crimp.

      I personally have not needed to neck turn my casings but some people claim it is needed. I have shot some of my stuff 5-6 times and it is still good.

      Comment

      • LR1955
        Super Moderator
        • Mar 2011
        • 3355

        #4
        Originally posted by VASCAR2 View Post
        A buddy gave me some brass 7.62 X 39 mostly mixed case, FC IMI, CBC ect. There was a thread on how to do this on AR15.com but its been long enough ago that it is no longer available to me. I was going to tumble the brass then re-size the brass with my Hornady 6.5 Grendel dies. I know I should reduce my powder charge and I figure I'll use the cheapest bullets I can find. I would assume there shouldn't be any trouble getting the 7.52X39 brass to enter the 6.5 G sizing die. I normally ream the flash hole and remove the crimp for the primer pocket. From looking at these cases I didn't notice any crimped primers. Is it normal for 7.62 X 39 to have crimped primers? Do most 7.62X39 use large rifle primers or do they use large and small primers? I've never loaded 7.62 X 39 so any insight would be appreciated. Thanks in advance!
        VC2:

        Since they are mixed brass a guy gave you, if it has been fired through another rifle -- particularly a AK -- you may not have much luck with it due to the sloppy chambers in AK's. However, either way, size it, load it, and shoot it. I think that the IMI brass I have can take about 28 grains of 2520 once it has been fire-formed. So, non fire-formed brass will take 25 or 26 grains and probably less if you use extruded powder. I would use TAC or something akin and about 25 grains of the powder. As for primers -- most of the 7.62 X 39 brass takes large primers so there you go. I believe Remington used to make 7.62 X 39 with small primer pockets but apparently that brass is long gone. Use any of the Large Rifle Primers as long as they are big enough to seat tightly into the pockets. No need for fillers.

        We used to get IMI 7.62 X 39 brass for about $.15 a piece not too long ago but the prices went way up. I still have 500 pieces of virgin IMI brass sitting around unused since Hornady started making Grendel brass. We used to have a real hard time getting Grendel brass but no more so you have some options.

        Watch the loads once you get some 7.62 X 39 brass formed. You will lose a bunch of velocity due to the decreased powder capacity and the primer pockets will probably open up after five shots or so. It was a necessity 'in the day' but really isn't necessary anymore unless you can get the brass real cheap and don't intend on anything serious past maybe 200 yards.

        LR1955

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        • longdayjake

          #5
          Just FYI. I bought some new small rifle primered remington last year. Not sure if it is still made but it was made as late as last year.

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          • LR1955
            Super Moderator
            • Mar 2011
            • 3355

            #6
            Originally posted by longdayjake View Post
            Just FYI. I bought some new small rifle primered remington last year. Not sure if it is still made but it was made as late as last year.
            LDJ:

            Good for you! I haven't been able to find any for quite a while. It is a better bet than the large primed 7.62 X 39 and I would opt for the small primed brass any time.

            LR55

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            • VASCAR2
              Chieftain
              • Mar 2011
              • 6218

              #7
              Thanks a lot for the information. I thought I might use the 7.62 X39 for close in varmint hunting or blasting ammo. I hate to loose brass that is worth .65 to $1.00 if I don't have to. Since the brass was free I thought I might fire form it to 6.5 G. I read where the case capacity on the 7.62 X 39 was less than 6.5 G so I'll use your suggestions on how to load them.

              Comment

              • LR1955
                Super Moderator
                • Mar 2011
                • 3355

                #8
                VC2:

                Yes, it is way less and your pressures are probably higher so keep the charges down. You can get pretty decent performance out of the brass so don't write it totally off as blasting brass. Guys have the same reasoning as you do for the use of cheaper 7.62 X 39 brass which is mostly hunting or running and gunning where the brass is flying into weeds and bushes.

                After I fireform the brass, I run an internal reamer through the fired brass to remove the donut that will appear. One pass lasts for the five or six times you will shoot the brass before the primer pockets open up too much. You won't get donuts in the real Grendel brass but you will when you fireform the 7.62 X 39 brass.

                LR1955

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                • #9
                  I've got a batch of KP (lapua) 7.62x39 I necked down and fireformed with 25-26 grains of TAC and 120 SMK's and at 100 yards it shot almost as accuratly and to the same point of impact as standard loads. Don't just write it off as blasting ammo, it will shoot quite well if using decent components. I also have not seen "donuts" form in that brass yet but it's something you should be prepared for. Maybe after more firings the thicker shoulder will extrude up enough to make it noticeable as I've only got 3 or so on it now.

                  Comment


                  • #10
                    I need help. I hear alot about fireforming so I bought some Rem 7.63x39 brass at a gunshow. I tried resizing them and crushed them in my press.

                    What is the trick to resizing the brass in prep to fireform? Do I need a different die?

                    Comment

                    • Dogue
                      Warrior
                      • Mar 2011
                      • 415

                      #11
                      Not sure why your brass is getting crushed. I only have a handfull of X39 but have run them through my sizing die and they resized just fine. I don't have enough to fireform yet since I only use free brass for this. I figure with bought brass plus components to fireform I might as well buy Hornady brass (or their loaded ammo which isn't much more than the brass alone).
                      Μολὼν λαβέ

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                      • #12
                        All use large primers that I know of and I have reformed around 700 pieces last year. A real pai in the bu-tocks. PMC, Fed, Rem, IMI, Win. All large. Crimps, you probably got mass produced military brass. Their about the only one that crimp much anymore. I would chuck it and get some other brass unless you dont mind swageing (sp) the pockets out. There are primers that are made for miltary brass at least in the 5.56 type. I also had trouble with brass after I fire formED due to the bolt eating the rims. Back off on gas to where your bolt operates at the least amount needed to save on chewing up brass. I notice 2 to 3 grains differance in case capacity but would have to say that they shot well. I didn't like having two different loads but not having good lapua/AA brass to use but at the time brass because it was scarce. It works and I have serveral hundred reforms and some loads for them. I use the good brass for precision work and reforms for all others.

                        Comment

                        • longdayjake

                          #13
                          I have heard that remington brass has a tendency to crush when sizing it down. I haven't had that issue but it apparently happens to many. Are your remingtons small or large rifle primered?

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                          • #14
                            I have lost track of time, but think it was about 3 years ago, I picked up 2000 rounds for IMI 7.62x39 brass from Widners.

                            I ran all of it through a 6.5 Grendel die and usually load with some 129 or 140 gr bulk bullets I bought from Midway. I generally used Win 748 powder and reduced lower end loads by about 1-1.5 gr and had very good results. Those loads would feed from magazine, cycle action and were accurate enough for fun shooting.

                            Just use a cartridge OAL gauge and check some empties to make sure they will chamber and eject without sticking and you should be ok.

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                            • LR1955
                              Super Moderator
                              • Mar 2011
                              • 3355

                              #15
                              Originally posted by Clarinath View Post
                              I need help. I hear alot about fireforming so I bought some Rem 7.63x39 brass at a gunshow. I tried resizing them and crushed them in my press. What is the trick to resizing the brass in prep to fireform? Do I need a different die?
                              CL:

                              A couple of things may be happening but it seems no matter what you do, one of every fifty or so will probably get crushed.

                              First off, use a good case lube and do get some lube inside the necks so the brass will extract easily. No need to go overboard with the lube. Just lube as you would any other brass.

                              Second -- start the brass straight into the die. Sometimes the brass moves a bit in the shell holder so you may want to ensure the brass isn't off center when it starts into the die.

                              Third -- when you start the brass into the die and it hits resistance from the neck, you may want to go slow and even back out once before finishing the sizing process.

                              You will probably still lose a piece of brass every thirty or fifty pieces no matter what you do so expect some losses.

                              LR55

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