Hydroforming brass- of donuts, soft necks, and saving ammo components

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  • Hydroforming brass- of donuts, soft necks, and saving ammo components

    First, hello all. I gained interest in the 6.5 Grendel in late November, and at the time the forum seemed to be off-line. glad to see it back up and running! I've already absorbed a lot of info, esp. on reloading, my topic today.
    Price of brass being what it is, I thought the best approach might be to form my own of 7.62X39. so I got 500 rounds from Gunbroker, and went to work. Turns out 400 were Winchester, and 100 were R-P, which seemed no big deal, but I was about to find out.
    As I'm sure you are all aware, the 6.5 takes most all the taper from the brass from base to shoulder, and leaves a pretty short neck.
    First thing I found out was that the first form would leave what you all seem to call a "donut" ring at the shoulder, an artifact of forcing the neck/shoulder junction. I found a vid on Youtube of a guy hydroforming this brass to 6.5G, in order to avoid throwing components downrange to finish the brass. He sent me a drawing of his hydroforming tool, and I had a friend with a lathe build me one. I had to weld a plug in a shellholder, cause you can hydraulically eject a primer instantly with the setup. It was working! I have all the W-W brass formed now, and have shot a few, miking them before and after, with 100% success.
    Now the R-P brass was a different story. It is small primered... what's up with that? No matter. I found that much more than a donut, it would crush the shoulder of the brass unmercifully. After ruining enough pieces experimenting, I found I could back the sizer die out about a nickel's thickness, and only get a small donut on the brass. However, this left the brass too long to fit the chamber. Yesterday I got the last piece of the puzzle together when I hydroformed the brass in the "too long" position. This blew the body out straight, so now when the brass is f/l sized it doesn't collapse. A way to use the *now short* 100 pieces of R-P brass.
    I s'pose a few pics would say it well, but there it is in print. I see where several are fighting the same bug-a-boos, and thought my experience might be of some help. Looking forward to comparing notes with you all.
  • txgunner00
    Chieftain
    • Mar 2011
    • 2070

    #2
    I've made a hydro forming die as well recently and had the same learning curve to deal with. Winchester brass was the easiest. IMI is a booger- very thick. I'll post up more info when I have more time.
    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.

    Comment


    • #3
      I gave up on trying to form 7.62x39 cases. I found that with the cost of buying primers, bullets, powder, gas to the range to fire form, and with the MUCH lower case life from the large rifle primers, the cases I ended up with were actually more expensive than simply buying Lapua or AA cases.

      However, it you either already have a bunch of 7.62x39 cases, it might be worth it. Even though I downloaded for fireforming, case life was only about 3 loadings before the primer pocket was simply too loose to be useful. I quit counting loadings on Lapua cases after I got past 6 loadings. Now, I rotate in one or two hundred new cases periodically, and out of 100 rounds fired, I will get one or two with case neck cracks or primer pockets that are too loose to safely use.

      Comment


      • #4
        Originally posted by noone View Post
        I found that with the cost of buying primers, bullets, powder, gas to the range to fire form, and with the MUCH lower case life from the large rifle primers, the cases I ended up with were actually more expensive than simply buying Lapua or AA cases.
        Cost and wasted components was the primary reason I looked into hydroforming instead of fire-forming. I use NO components at all to hydroform, and it has done a very nice job for me.
        Now, whether or not I will have short case life from large primer pockets remains to be seen. Mebbe so.... but at my production cost of $.20 a case, I'll use 'em as long as they'll last, and see what's best then. The cost of new brass is getting more reasonable at least.
        Anyone care to conjecture why a large primer pocket might not have long life?

        Comment

        • longdayjake

          #5
          I have personally been able to get at least 6 loadings from winchester casings as long as I don't go overboard with the charges. I have also found that the slower the powder I use the less life my LRP brass lasts. I don't know why though. If you are wearing out that LRP brass that fast then you are really trying to push the velocities.

          Comment

          • longdayjake

            #6
            Just curious but what would it cost me to have your friend make me one too?

            Comment

            • pinzgauer
              Warrior
              • Mar 2011
              • 440

              #7
              Originally posted by noone View Post
              I gave up on trying to form 7.62x39 cases. I found that with the cost of buying primers, bullets, powder, gas to the range to fire form, and with the MUCH lower case life from the large rifle primers, the cases I ended up with were actually more expensive than simply buying Lapua or AA cases.

              However, it you either already have a bunch of 7.62x39 cases, it might be worth it. Even though I downloaded for fireforming, case life was only about 3 loadings before the primer pocket was simply too loose to be useful. I quit counting loadings on Lapua cases after I got past 6 loadings.
              I've got IMI 7.62x39 fireformed to grendel on their 8th loading. Primer pockets are now noticeably looser, but are still shooting fine.

              Early on I was only getting about 5 reloads before seeing split necks, but it was nearly always in a spot where the feedramps scored the brass. Now they are broken in and I polished the ramp corners and I'm not seeing that problem. Likewise, some of the worst loose primer pockets are due to higher pressure loads due to improper COAL. My later batches have not loosened as much, though you can tell a difference.

              I'm not sure I'd buy RP or Win 7.62x39 brass at this point, the Hornady is too available. But if you got the original wideners deal on IMI brass it works fine.

              And forget about "wasting" ammo fireforming, it shoots fine. One of my fireform loads has turned in 1/2 moa groups, though we mostly use it for plinking.

              Comment


              • #8
                Originally posted by longdayjake View Post
                Just curious but what would it cost me to have your friend make me one too?
                I sent ya a PM

                Comment

                • durhamster

                  #9
                  I have 2K Winchester 7.63X39 Brass.
                  Have reloaded 200 to fireform.
                  My new 264 BHW upper comes in next week.
                  I like the idea of hydroforming.
                  can you send me the spec. I have a frend who can mechine it for me.
                  Thank you for your help.


                  Originally posted by HammerMTB View Post
                  First, hello all. I gained interest in the 6.5 Grendel in late November, and at the time the forum seemed to be off-line. glad to see it back up and running! I've already absorbed a lot of info, esp. on reloading, my topic today.
                  Price of brass being what it is, I thought the best approach might be to form my own of 7.62X39. so I got 500 rounds from Gunbroker, and went to work. Turns out 400 were Winchester, and 100 were R-P, which seemed no big deal, but I was about to find out.
                  As I'm sure you are all aware, the 6.5 takes most all the taper from the brass from base to shoulder, and leaves a pretty short neck.
                  First thing I found out was that the first form would leave what you all seem to call a "donut" ring at the shoulder, an artifact of forcing the neck/shoulder junction. I found a vid on Youtube of a guy hydroforming this brass to 6.5G, in order to avoid throwing components downrange to finish the brass. He sent me a drawing of his hydroforming tool, and I had a friend with a lathe build me one. I had to weld a plug in a shellholder, cause you can hydraulically eject a primer instantly with the setup. It was working! I have all the W-W brass formed now, and have shot a few, miking them before and after, with 100% success.
                  Now the R-P brass was a different story. It is small primered... what's up with that? No matter. I found that much more than a donut, it would crush the shoulder of the brass unmercifully. After ruining enough pieces experimenting, I found I could back the sizer die out about a nickel's thickness, and only get a small donut on the brass. However, this left the brass too long to fit the chamber. Yesterday I got the last piece of the puzzle together when I hydroformed the brass in the "too long" position. This blew the body out straight, so now when the brass is f/l sized it doesn't collapse. A way to use the *now short* 100 pieces of R-P brass.
                  I s'pose a few pics would say it well, but there it is in print. I see where several are fighting the same bug-a-boos, and thought my experience might be of some help. Looking forward to comparing notes with you all.

                  Comment

                  • infidel470

                    #10
                    @ HammerMTB
                    Would it it be appropriate to ask for price on the hydroforming tool?

                    Comment

                    • StoneTower

                      #11
                      The resizing die is the tool and you need a punch of the correct size. I took a letter drill bit out of a Harbor Freight set and drilled a piece of stainless steel bar to act as a handle/striking surface. I epoxied it together and it works well.

                      Comment

                      • longdayjake

                        #12
                        I took a letter drill bit out of a Harbor Freight set and drilled a piece of stainless steel bar to act as a handle/striking surface. I epoxied it together and it works well.
                        i would like to see a picture of this little contraption.

                        Comment


                        • #13
                          Me too!

                          Comment


                          • #14
                            This was the video I saw

                            To me, it seemed like a fairly intuitive process.

                            Hoot

                            Comment

                            • pinzgauer
                              Warrior
                              • Mar 2011
                              • 440

                              #15
                              Originally posted by noone View Post
                              However, it you either already have a bunch of 7.62x39 cases, it might be worth it. Even though I downloaded for fireforming, case life was only about 3 loadings before the primer pocket was simply too loose to be useful.
                              I'm seeing 7-8 loadings with IMI before splits or loose primer pockets.

                              As LR1995 pointed out, hydraforming is quite a chore compared to just shooting. I found a 90g hornady load I use to fireform which shoots to same point of impact as my 120g full power load. And is quite accurate, so I don't see the perceived downside to fireforming.

                              I went down this path when grendel brass was unobtainium and IMI 7.62x39 brass was cheap and available. Now I'd probably just buy hornady brass, or ammo on one of the deals. Do the math, you'll be surprised. When midway had the Hornady factory at $18/box, it was not worth buying brass once you factored multiple brass usage. (If your time is worth anything)

                              Comment

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