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Really narrowing down my load

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  • blockfort
    Senior Member
    • Oct 2011
    • 1183

    Really narrowing down my load

    I've been testing my 308 by loading 168 SMK's over IMR 4064.

    After a few tests, I narrowed down the range to 42.5-44.5 and tested 8 shot groups in 0.5gr increments:



    I decided that both the high and low end of the test showed well, so I did another test of two zones, 42.6-34.4 & 44.4-45.2, by 0.2 gr increments.

    Here's the result of the 0.2gr increment test (1" grid spacing). Each circle represents the location and size of each 5-shot group. For "size" I am using the average distance all shots in each group, from the center of their group.



    Seems like 44.4-45.2 are a bit scattered, as are 42.6 & 42.8, but right in the middle, 43.0, 43.2, and 43.4 are not only small, but hitting in almost exactly the same location. This is what I imagine I should be looking for in the OCW method.

    Looking at just those three loads, here are the actual hits:



    Next test will be 43.0-43.4 with 0.1gr increments. Hopefully they'll be all close to each other, and I can go with something in the middle and work on load length next.
    Last edited by blockfort; 08-03-2016, 11:11 PM.
  • #2
    kcheung2
    Veteran Member
    • Aug 2012
    • 4387

    I don't know if going down to 0.1 grain increments would be helpful or even possible. 4064 is pretty chunky so it's hard to be at the exact 0.1 grain that you want to be.
    ---------------------
    "There is no "best." If there was, everyone here would own that one, and no other." - DSB

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    • #3
      avcrew
      Member
      • May 2013
      • 271

      Also did a load test with 168 grain SMK and 4064 using 41 to 44 grains.

      Tested in a 1 in 10 twist 20" barrel, bolt action.

      Best 5 shot group at 100 yards was .5 MOA using 42 grains of 4064.

      Comment

      • #4
        Sky_DiveR
        Veteran Member
        • Dec 2008
        • 3017

        Looks like it's time to start using different lengths to see if any one load stands out. Don't think going down to 0.1 rains is gonna make much difference (as mentioned above). Did you start out your lengths at the minimum so you only have one way to adjust?

        What rifle/barrel are you shooting these out of?

        What are the other particulars (ie: temp, wind, etc)?

        Comment

        • #5
          blockfort
          Senior Member
          • Oct 2011
          • 1183

          The rifle is a Browning A-Bolt Target, 28" 1:10 barrel.

          If I don't do one more test to confirm/determine a single load to work with for load length, which load should I use?

          All tests were done at 2.8OAL, so yeah, I only have one direction to go with load length. I didn't start long because my rifle seems to have a very long chamber. To hit the lands, I'd have to load almost 1/8" longer, leaving only 0.1" of bullet in the neck of the case (not including the boat tail, which doesn't touch the neck).

          Sent from my SM-G920V using Tapatalk

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          • #6
            RNE228
            Senior Member
            • Oct 2013
            • 2458

            I need to rework my 308 loads; I was shooting Sierra 165-BTHP Gamekings out of Federal Match brass with 4064. Nice for long shots on Wyoming antelope out of a Rem 700V. I lost my notes on my 308 and 30-06 loads though(had also loaded 30-06 with Speer 150-SoftPoint spitzer that worked well for antelope).

            I found as others mentioned; getting down in the .1gr increments with extruded powder like 4064 is very difficult to almost impossible.

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            • #7
              trackcage
              Senior Member
              • Apr 2015
              • 1777

              Originally posted by blockfort
              The rifle is a Browning A-Bolt Target, 28" 1:10 barrel.

              If I don't do one more test to confirm/determine a single load to work with for load length, which load should I use?


              All tests were done at 2.8OAL, so yeah, I only have one direction to go with load length. I didn't start long because my rifle seems to have a very long chamber. To hit the lands, I'd have to load almost 1/8" longer, leaving only 0.1" of bullet in the neck of the case (not including the boat tail, which doesn't touch the neck).

              Sent from my SM-G920V using Tapatalk
              Based on your third chart, 43.0gr

              Comment

              • #8
                blockfort
                Senior Member
                • Oct 2011
                • 1183

                Originally posted by trackcage
                Based on your third chart, 43.0gr
                Even though 42.8 is quite a way off? Maybe 43.0 is at the end of the node.

                Comment

                • #9
                  blockfort
                  Senior Member
                  • Oct 2011
                  • 1183

                  Originally posted by RNE228
                  I need to rework my 308 loads; I was shooting Sierra 165-BTHP Gamekings out of Federal Match brass with 4064. Nice for long shots on Wyoming antelope out of a Rem 700V. I lost my notes on my 308 and 30-06 loads though(had also loaded 30-06 with Speer 150-SoftPoint spitzer that worked well for antelope).

                  I found as others mentioned; getting down in the .1gr increments with extruded powder like 4064 is very difficult to almost impossible.
                  My scale measures to 0.05gr, I think I can trickle to 0.1 easily.

                  Sent from my SM-G920V using Tapatalk

                  Comment

                  • #10
                    RNE228
                    Senior Member
                    • Oct 2013
                    • 2458

                    The 4064 extrusions do not seem to be that consistent in my experience. Not a problem with scale accuracy, more a issue of consistent size and weight of the powder stick(4064 is like sticks of broken pencil lead/graphite).

                    Originally posted by blockfort
                    My scale measures to 0.05gr, I think I can trickle to 0.1 easily.

                    Sent from my SM-G920V using Tapatalk

                    Comment

                    • #11
                      blockfort
                      Senior Member
                      • Oct 2011
                      • 1183

                      Originally posted by RNE228
                      The 4064 extrusions do not seem to be that consistent in my experience. Not a problem with scale accuracy, more a issue of consistent size and weight of the powder stick(4064 is like sticks of broken pencil lead/graphite).
                      I trickle all my rounds. Maybe it's not an issue for me?

                      Sent from my SM-G920V using Tapatalk

                      Comment

                      • #12
                        ExtremeX
                        Calguns Addict
                        • Sep 2010
                        • 7160

                        Originally posted by trackcage
                        Based on your third chart, 43.0gr
                        This...

                        I would do another ladder and explore the results around the 43gr range +/- .2gr

                        Make enough to get some good data...
                        ExtremeX

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                        • #13
                          RNE228
                          Senior Member
                          • Oct 2013
                          • 2458

                          I did too; maybe you have a little more finesse than me

                          Originally posted by blockfort
                          I trickle all my rounds. Maybe it's not an issue for me?

                          Sent from my SM-G920V using Tapatalk

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