Bullet size to die ball size.

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  • 6.5 mm Shoot
    Bloodstained
    • Apr 2016
    • 40

    Bullet size to die ball size.

    Hi all.

    Due to a post that I made about a range testing some rounds and one round going way up in FPS I believed that the spike was caused by bullet set back. Some said that I needed a better set of dies than the Lee that I am using and didn't need to crimp the cases, I have always crimped my cases till this last set of loads and thought I would try what the cool kids are doing.

    It didn't work out for me I ended up with a hot shot that blew out the primer and gave me a FPS that was 2590 FPS that should have been around 2400 FPS.

    So what I just did was check the bullet size. I got .262 for the Hornady 6.5 SST 123gr. Then checked Sierra Game King 6.5 HPBT 130gr and got .2615 to .262.( three out of the five measured were .2615) Then I checked Hornady 6.5 SST 129gr and got .262. Then I took my Lee die apart and the ball on the decapper rod is .261 at the widest part. Now I have a Hornady die coming and I will measure it when it gets here. My question to all of you is what do your dies measure at that point?

    In my dies case I would say .001 isn't enough to hold a bullet in place under recoil or loading. I would think it should be some where around .003 smaller than the bullet to get a tight grip. Any thoughts? Because I was just guessing. I know when we put sealed bearings on a pump shaft it was always over sized .002 to keep the inner race from turning on the pump shaft. Then that was hard steel on harder steel.

    Any thoughts on the above or standers set by the industry that are known would be of great help.

    Thank you much for any information that you can offer.
    Last edited by 6.5 mm Shoot; 04-21-2016, 02:54 AM.
    May each day bring you at least one pleasure.
  • Cornbread
    Warrior
    • Dec 2015
    • 288

    #2
    If your .264(6.5) bullets measured .262 either your caliper is fubar or you are not measuring in the right spot ie behind the ogive towards the shank. Your bullets should measure .264.

    Comment

    • Drillboss
      Warrior
      • Jan 2015
      • 894

      #3
      Are you using calipers or a micrometer?

      I had a similar experience with my calipers indicating 0.262" to 0.263". The micrometer came a lot closer to 0.264".

      Comment

      • 6.5 mm Shoot
        Bloodstained
        • Apr 2016
        • 40

        #4
        I guess I need a new caliper then because that is what I measured. I thought that a .264 bullet should be .264. No place on this bullet will it measure .264 according to this caliper.
        Last edited by 6.5 mm Shoot; 04-21-2016, 02:47 AM.
        May each day bring you at least one pleasure.

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        • kmon
          Chieftain
          • Feb 2015
          • 2095

          #5
          You will need the opening in the neck .002 or preferably .003 smaller than the bullet to use neck tension alone to hold the bullet securely. The more consistent the neck tension the more consistent the ammo will be.

          Comment

          • 6.5 mm Shoot
            Bloodstained
            • Apr 2016
            • 40

            #6
            Cornbread did you measure a bullet or are you just stating what a 6.5 bullet should be. If you measured a bullet and got .264 what brand caliper did you use? Where did you get it?
            May each day bring you at least one pleasure.

            Comment

            • LRRPF52
              Super Moderator
              • Sep 2014
              • 8569

              #7
              I just measured 10 different projectiles from my collection, including 123gr SST, 123gr AMAX, 120gr Scenar-L, 120gr GMX, 120gr TSX, 160gr Round Nose, and they are all .2641"-.2648" in diameter.

              Clean your caliper blades and check zero indication.

              If any of your 6.5mm bullet show something less than .264", your calipers are jacked. Use the square parts of the jaws, not the blades, and do it at the bullet shank, not the ogive.

              You confirmed what I suspected from the start though, in that you don't have sufficient neck tension at .001".

              I just measured several sized cases inside the necks, and they all measure .259", giving me .006" neck tension.
              NRA Basic, Pistol, Rifle, Shotgun, RSO

              CCW, CQM, DM, Long Range Rifle Instructor

              6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

              www.AR15buildbox.com

              Comment

              • Cornbread
                Warrior
                • Dec 2015
                • 288

                #8
                If the bullets are 264 and you got 261 on the exp that's .003. Of course given the bullet measurement is suspect who knows. The best way is to measure the necks after sizing and after seating and subtract the difference.

                Comment

                • LRRPF52
                  Super Moderator
                  • Sep 2014
                  • 8569

                  #9
                  Originally posted by Cornbread View Post
                  If the bullets are 264 and you got 261 on the exp that's .003. Of course given the bullet measurement is suspect who knows. The best way is to measure the necks after sizing and after seating and subtract the difference.
                  He's getting .262 for his bullets, and .261 on the expander ball. His calipers are jacked, but using the same tool indicates .001" neck tension, which is why he's having set back and inertia-based COL growth.
                  NRA Basic, Pistol, Rifle, Shotgun, RSO

                  CCW, CQM, DM, Long Range Rifle Instructor

                  6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

                  www.AR15buildbox.com

                  Comment

                  • sneaky one
                    Chieftain
                    • Mar 2011
                    • 3077

                    #10
                    Yes, change the bullets out !

                    Then get some 1000-3000 grit sandpaper from a local automotive shop--- Hone the center ball- down with a drop or 5 of h2o--use your drill , at semi slow speeds.

                    Polish it ABAP. Easiest way to tweak the neck tensions. Pm me if lost, L52 needs a week off... He's bizzyer than I !

                    .263-.2645 are the units to use. As for bullet O.D. units. Use the calipers to verify outside diamaters.


                    Maybe our pal TX Gunner can chime in of our shared uses of the Lee sizing die--- 0nly used for Ak, & only AK brass.

                    The junk from china , russkie, =too thin to have a quality stamp upon it. Ak brass has a 1 time use mentality. We can get 3-5- shots--Meh,,,


                    If sized in my Forster die, it's at .264. ZERO neck tension ! I relube a tic--- then run thru my 2008 Lee Grrr dies=== 259-260 ID . All is well at that point,,, until the primer pockets just get too loose to be trusted by feeling , pushing one home- then recycle the brass.


                    Side note- I can get same performance from junky brass , as same as Lapua stuff. In the speed scenarioes

                    I will redirect my hunt loads thru the cheapo brass- bye bye into the snowbanks ! Yahooo


                    Forgot, 4 years ago, I found a 200 rnd. lot of Lapua AK brass,,,, 12 bucks. That's my future throwaway brass for hunts. Fireformed nicely. Always be looking for a deal..
                    Last edited by sneaky one; 04-22-2016, 01:16 AM.

                    Comment

                    • SDguy
                      Warrior
                      • Oct 2015
                      • 367

                      #11
                      cleaning and zeroing a caliper

                      I assume you are using a digital caliper. Has anyone showed you yow to clean your caliper blades with a clean sheet of paper? Suspect you may re-zero your caliper after cleaning the blades / tips and see a .003" diff very quickly.

                      Comment

                      • 6.5 mm Shoot
                        Bloodstained
                        • Apr 2016
                        • 40

                        #12
                        SDguy I would guess that you clamp down on a clean sheet of paper then pull the calipers off the paper. That got me a extra .001. Now the bullets measure .263. Oh, yes I did zero after I used the paper cleaning trick. I have ordered a new set of calipers. The thing of it is they are only good for a + or - of .001. So I might not get any better reading with them. I can't spend $200 for the ones that are + or - .0001.
                        May each day bring you at least one pleasure.

                        Comment

                        • 6.5 mm Shoot
                          Bloodstained
                          • Apr 2016
                          • 40

                          #13
                          I picked up a new caliper and started over. I got .264 to .2645 on the bullets.

                          I measured the Lee sizing ball on the decaping rod and got .264. Little wonder I had problems with setback.

                          I measured the Hornady sizing ball on the deacaping rod and got .262.

                          The plan is to take .002 off the ball of the Lee die with 1000 grit sand cloth. Then I am going to set them back for use as a extra set.

                          I would like to thank everyone for their help and information.
                          Last edited by 6.5 mm Shoot; 04-23-2016, 11:16 AM.
                          May each day bring you at least one pleasure.

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