Collapsed Shoulder

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  • rasp65
    Warrior
    • Mar 2011
    • 660

    Collapsed Shoulder

    I recently reloaded some brand new ALEXA headstamped brass. The first 50 reloaded fine. The last 50 I had 5 cases completly collapse the shoulder and 8 with bulges at the shoulder like you get when fireforming 7.62X39 cases. I was using the same 120 SMKs with HBN coating. All the cases were processed the same way, they were run over my Redding carbide sizing button and neck turned to the same thickness. Has anyone else ever experienced such problems?
  • LR1955
    Super Moderator
    • Mar 2011
    • 3355

    #2
    Originally posted by rasp65 View Post
    I recently reloaded some brand new ALEXA headstamped brass. The first 50 reloaded fine. The last 50 I had 5 cases completly collapse the shoulder and 8 with bulges at the shoulder like you get when fireforming 7.62X39 cases. I was using the same 120 SMKs with HBN coating. All the cases were processed the same way, they were run over my Redding carbide sizing button and neck turned to the same thickness. Has anyone else ever experienced such problems?
    R65:

    Good to see you back.

    Negative from me. Haven't crushed brass, had dimpled shoulders, or bulged the shoulder junction.

    Why did it happen with you? Can only speculate.

    Normally excessive lube on the shoulders can cause them to get dimpled. This happens with thick lubes that come in tubes that you squirt onto stamp pads.

    Sizing die set too tight crushes the shoulders back is another speculation.

    Expander button not set deeply enough, thus jamming the neck of the brass into the neck part of the sizing die.

    No lube inside the neck can allow for the expander button to exert huge amounts of force downward on the shoulder, crushing the necks and or bulging the brass.

    Expander button too big may also cause problems.

    Like we discussed on the earlier forum, neck turning Lapua brass is unnecessary for good bolt rifles and is totally unnecessary for gas guns but I doubt neck turning them caused the problems you are seeing unless you really took off a lot of brass -- thus weakening the necks.

    Advice FWIW.

    Re-check the depth of your seating die.

    Ensure your expander button is down sufficiently that it isn't getting the neck jammed between it and the inside of the neck part of the die.

    Get some Dillon spray lube and use it. Or at least lube the inside of the necks somehow before running them through any type of die -- carbide or not.

    LR1955

    Comment

    • rasp65
      Warrior
      • Mar 2011
      • 660

      #3
      Thanks LR good to be back. Nothing had changed in any of my settings. I miked the expander button and it was correct. Normally my sizing die has pretty good contact with the shell holder. But in this case i just ran the necks to get uniform size for turning. I pulled the bullets on the ones that were completely collapsed and found long scratches on the contact surfaces. I can fit the cases into my case guage so I am considering fireing them to blow them back out. Just have never experienced anything like this before.

      Comment

      • LR1955
        Super Moderator
        • Mar 2011
        • 3355

        #4
        Originally posted by rasp65 View Post
        Thanks LR good to be back. Nothing had changed in any of my settings. I miked the expander button and it was correct. Normally my sizing die has pretty good contact with the shell holder. But in this case i just ran the necks to get uniform size for turning. I pulled the bullets on the ones that were completely collapsed and found long scratches on the contact surfaces. I can fit the cases into my case guage so I am considering fireing them to blow them back out. Just have never experienced anything like this before.
        R65:

        Sorry -- I guess this happened when you were seating the bullets? In that case most likely it is because the sizing die is real tight on the necks and if you didn't expand them, the force of the bullet seating crushed the shoulders.

        Are you sure you are using the Grendel seating die? Not sure what your set up is but I use a Redding T-7 Turret and right next to my Grendel dies are 6 BR and 6 AR so in my case it is possible for me to try and seat a bullet into a Grendel case using a 6 BR or 6 AR die.

        Anyway, might as well remove your sizing and seating dies and clean them. Could be something stuck inside of them causing the problem.

        LR1955

        Comment

        • rasp65
          Warrior
          • Mar 2011
          • 660

          #5
          I dont have that problem with mistaking 6mm AR but I wish I did. These were brand new cases, all I did was to run the expander ball in the necks and I turned it out as far as I could so I wouldn't touch the necks with the die. I reloaded them with a lighter charge and am contemplating shooting them. What do you think?

          Comment

          • LR1955
            Super Moderator
            • Mar 2011
            • 3355

            #6
            Originally posted by rasp65 View Post
            I dont have that problem with mistaking 6mm AR but I wish I did. These were brand new cases, all I did was to run the expander ball in the necks and I turned it out as far as I could so I wouldn't touch the necks with the die. I reloaded them with a lighter charge and am contemplating shooting them. What do you think?
            Rasp:

            Hmmm. More information or perhaps I didn't see it all before. I think I know what you were doing now. You were just truing up the inside of the necks using the expander ball without using lube or full length resizing?

            If you didn't lube the inside of the necks prior to doing this, most likely the friction caused a lot of force to be pushed down on the shoulder. A dry expander ball being pushed through a dry neck can cause problems.

            If you want to size the brass or true up the necks, lube the brass and full length resize. It won't hurt a thing and certainly won't cause accuracy problems.

            I know -- carbide expander ball. Doesn't matter. Lube the brass before working any part of it.

            Might as well shoot them if they chamber and the bolt goes into battery.

            Then lube and size using the entire sizing die. Bet it won't happen again.

            LR1955

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