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    First Time Necking Down Brass - Got a Question

    Fairly experienced reloader... never necked brass up or down before though.
    I need to make 6mm-284 wildcats and am going to do it by necking down 6.5mm-284 Norma brass... seems pretty straightforward based on the reading I've done.
    However, I'm a fan of and typically use Redding Type-S Neck sizing dies. All my reloading is for hunting (not bench rest) guns so my typical process is to bump a thou using the Redding body die that doesn't touch the neck and then neck size using the bushing die.
    I've read that I shouldn't try to neck down with a bushing but a full length sizing die. I wouldn't otherwise use a full length die... do I need to buy one just to resize the necks or is there some good way to neck down using bushings?
    Also, do I need to anneal brand new brass before necking down from 6.5mm to 6mm? I'm assuming I'll probably have to turn them when I'm done.
    TIA
    Last edited by meltingfeather; 01-11-2018, 07:21 PM.

    #2
    Use the dies you have.

    Annealing depends on what brsss you have

    Comment


      #3
      Originally posted by bboswell View Post
      Use the dies you have.

      Annealing depends on what brsss you have
      Thanks for the reply... I'll body size one and cram it into a 0.271 bushing and see what happens!
      It's new Lapua 6.5mm-284 Norma, which says it's factory annealed, so I'll skip that part.

      Comment


        #4
        Originally posted by meltingfeather View Post
        Thanks for the reply... I'll body size one and cram it into a 0.271 bushing and see what happens!
        It's new Lapua 6.5mm-284 Norma, which says it's factory annealed, so I'll skip that part.
        I do this same thing necking down Lapua 30-06 to 280 which is a little more change than you are making but I have to run it through the body die which sizes the neck some as well and then run through the neck die. If I don't I crush some cases.

        Be sure to check your neck thickness after you do this as the necks will thicken when necking down, don't be surprised if you have to neck turn.

        Comment


          #5
          Will the s die bushing go all the way down to size the entire neck?

          Watch for a donut at the shoulder also. You can inside neck ream or turn necks after running a mandrel and cut into the shoulder to remove excessive brass build up in that area.

          Comment


            #6
            Originally posted by bboswell View Post
            I do this same thing necking down Lapua 30-06 to 280 which is a little more change than you are making but I have to run it through the body die which sizes the neck some as well and then run through the neck die. If I don't I crush some cases.
            No annealing I assume?
            I'll go slow and use plenty of lube.

            Originally posted by bboswell View Post
            Be sure to check your neck thickness after you do this as the necks will thicken when necking down, don't be surprised if you have to neck turn.
            Will do. I'm going to measure thickness before and after just out of curiosity.
            Theoretically the thickness should go up by .264/.243 or 8.5%, which ought to be a touch over one thou, depending on the starting thickness.
            I'll post up results... always like threads that close the loop.
            Thanks for the input.

            Comment


              #7
              You will need to use a neck reamer after to remove the donut

              Comment


                #8
                Originally posted by cattlelackranch View Post
                Will the s die bushing go all the way down to size the entire neck?
                I can adjust it to go down as far as I need it to.

                Originally posted by cattlelackranch View Post
                Watch for a donut at the shoulder also. You can inside neck ream or turn necks after running a mandrel and cut into the shoulder to remove excessive brass build up in that area.
                Originally posted by Team Roper View Post
                You will need to use a neck reamer after to remove the donut
                Thanks, y'all. I'll keep an eye on it.
                My plan is to neck turn into the shoulder before I neck down to prevent this as much as possible, but I'll keep an eye on it. May end up neck reaming...
                I'll post up once I get there.
                Last edited by meltingfeather; 01-15-2018, 08:37 AM.

                Comment


                  #9
                  Originally posted by meltingfeather View Post
                  I can adjust it to go down as far as I need .


                  Good to know. I've switched primarily to wilson hand dies and I know they don't reach the shoulder.

                  What kind of velocities are you trying to reach? It sounds like it will be a screamer.

                  Comment


                    #10
                    Your bushing will not reach the last small section of neck. This will create a false shoulder that will fire form out but can leave a donut. I would advise to skim the necks after sizing, fireforming, and sizing again. After the second full length sizing operation, run brass through expanding mandrel prior to neck turning.

                    Comment


                      #11
                      Originally posted by cattlelackranch View Post
                      What kind of velocities are you trying to reach? It sounds like it will be a screamer.
                      The one in 9" twist is fast enough to get me into the sweet spot of 95-100 gr. and I'm expecting north of 3,100 fps.
                      Originally posted by JakeGraves View Post
                      Your bushing will not reach the last small section of neck. This will create a false shoulder that will fire form out but can leave a donut. I would advise to skim the necks after sizing, fireforming, and sizing again. After the second full length sizing operation, run brass through expanding mandrel prior to neck turning.
                      You're saying wait to turn until after fire forming?
                      Most of what I'm hearing is turn before sizing to minimize the possibility of donut formation.

                      Comment


                        #12
                        Originally posted by meltingfeather View Post
                        The one in 9" twist is fast enough to get me into the sweet spot of 95-100 gr. and I'm expecting north of 3,100 fps.

                        You're saying wait to turn until after fire forming?
                        Most of what I'm hearing is turn before sizing to minimize the possibility of donut formation.
                        The correct way is to use a non bushing die. If you use a bushing die, it will leave a .050” or so section of unsized neck. Even after neck turning, the donut can form from thicker brass in shoulder migrating down into the neck. You can feel this when running brass through the expanding mandrel.

                        Comment


                          #13
                          Originally posted by JakeGraves View Post
                          The correct way is to use a non bushing die. If you use a bushing die, it will leave a .050” or so section of unsized neck. Even after neck turning, the donut can form from thicker brass in shoulder migrating down into the neck. You can feel this when running brass through the expanding mandrel.
                          We'll see... I've read that I can prevent this by turning into the shoulder.
                          I'd prefer not to buy an additional die just for this process, but I will if I have to.
                          I'm going to trial run it with the bushing die for the very small adjustment I'm making with a few cases and go from there.
                          My process:
                          • Full length size
                          • Measure neck thickness
                          • Neck turn a thou off and just into the shoulder
                          • Measure neck thickness
                          • Neck size for appropriate tension
                          • Fire form
                          • Bump shoulder 1 thou
                          • Neck turn to desired thickness (14 thou).
                          • Inspect for donuts.



                          Thanks for the input.

                          Comment


                            #14
                            First Time Necking Down Brass - Got a Question

                            So the first test batch of 10 is ready for loading.
                            Interesting that the thickness went up just as predicted... from 0.015” to 0.016”. Seems elementary, but also unexpected that it would happen in accordance with first principles.

                            6.5mm on the left, necked down to 6mm on the right:



                            Turned back down to 0.015” and about 0.002” into the shoulder, chamfered, and ready for fire forming:

                            Comment


                              #15
                              Originally posted by meltingfeather View Post
                              So the first test batch of 10 is ready for loading.
                              Interesting that the thickness went up just as predicted... from 0.015” to 0.016”. Seems elementary, but also unexpected that it would happen in accordance with first principles.

                              6.5mm on the left, necked down to 6mm on the right:



                              Turned back down to 0.015” and about 0.002” into the shoulder, chamfered, and ready for fire forming:
                              looking great!

                              What neck turner are you using?

                              Comment

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