123 Amax, SST testing

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  • Cornbread
    Warrior
    • Dec 2015
    • 288

    123 Amax, SST testing

    18" BHW 264 lbc.
    Ran a ladder with 123 Amax and 8208. 26.4 to 28.5 gr. in.3 gr increments. 2.252 coal hornady brass, CCI 41
    Velocity topped out at 2509 at 28.2 gr. at 28.5 velocity was the same.
    There was 2 distinct nodes. One around 27 gr and the other close to max.
    All 8 rounds were in about 1.5". I loaded several at 28 gr and got this. Ouch.



    Really surprised. At this point I decided to start changing the coal as I really wanted to be closer to 2500 fps.

    28 gr. 2.266 coal



    28 gr 2.283



    28 gr 2.295. This was max comfortable length with the asc mag. At 2.3 the tips were touching tge inside of the mag.

  • Cornbread
    Warrior
    • Dec 2015
    • 288

    #2
    123 gr sst 28 gr 2.285



    2 3 shot groups sane target. Not sure why they were walking right other than the wind had picked up and was pushing that direction.

    Comment

    • 1911man
      Warrior
      • May 2015
      • 482

      #3
      Looks like you had a real nice 5 shot group there with the one loaded to 2.283. Your velocity is right on par with what I have seen out of my 18" BHW 1x9 twist. 28.5 grains of XBR is the sweet spot in my rifle and it averages in the upper 2400's, I dont have my book in front of me but I think my 28.5 grain load with the 123 AMAX averages 2480-2490. The best OAL I found was in the 2.255 range. Its not my favorite load in this rifle but it is a good one and very temp stable. I think XBR is the best all around powder for this cartridge.

      Comment

      • BluntForceTrauma
        Administrator
        • Feb 2011
        • 3897

        #4
        Great report, and glad your careful work paid off!

        There's a theory out there that tuning loads for velocity is for, well, velocity, but that tuning seating depth is for accuracy. I don't know enough about it, but it seems your particular experience here bears that out.
        :: 6.5 GRENDEL Deer and Targets :: 6mmARC Targets and Varmints and Deer :: 22 ARC Varmints and Targets

        :: I Drank the Water :: Revelation 21:6 ::

        Comment

        • holmess89
          Unwashed
          • May 2015
          • 7

          #5
          I am currently in the process of load develpopment, and I am loading all of my rounds at 2.300 COAL. Using the Hornady bullet comparator, that is 1.717" to the ogive and the chamber guage measures 1.84" to the lands. Based on your results it seems I am over doing it with the OAL, I have been getting very sub par groups from my 20" BHW barrel (bouncing from just over MOA to 3.5 MOA). I have only tested with BL-C(2) so far, but 8208 XBR is up next. What do ya'll think?

          Comment

          • Cornbread
            Warrior
            • Dec 2015
            • 288

            #6
            Originally posted by holmess89 View Post
            I am currently in the process of load develpopment, and I am loading all of my rounds at 2.300 COAL. Using the Hornady bullet comparator, that is 1.717" to the ogive and the chamber guage measures 1.84" to the lands. Based on your results it seems I am over doing it with the OAL, I have been getting very sub par groups from my 20" BHW barrel (bouncing from just over MOA to 3.5 MOA). I have only tested with BL-C(2) so far, but 8208 XBR is up next. What do ya'll think?
            I would definitely try a different powder. From what I gather 8208 is very popular. I may try some AR comp. There is not much data for it though. I would usually adjust the powder charge first but in this case I had a velocity where I wanted to be. I will probally adjust the charge weight a bit at the 2.28 coal and see what happens. My goal is to find a consistent sub moa load for both bullets at 2450-2500 fps.

            Comment

            • 1911man
              Warrior
              • May 2015
              • 482

              #7
              Originally posted by holmess89 View Post
              I am currently in the process of load develpopment, and I am loading all of my rounds at 2.300 COAL. Using the Hornady bullet comparator, that is 1.717" to the ogive and the chamber guage measures 1.84" to the lands. Based on your results it seems I am over doing it with the OAL, I have been getting very sub par groups from my 20" BHW barrel (bouncing from just over MOA to 3.5 MOA). I have only tested with BL-C(2) so far, but 8208 XBR is up next. What do ya'll think?
              No matter what you do your going to have a large jump to the lands if you want to load them short enough to fit in a magazine. I started out loading in the 2.250 range simply because I noticed that is where Alexander arms, precision ammo, etc was loading their amax ammo at the time. I have not tried to go any longer since I have had fine results. The problem I have with tuning the overall length is that if I shoot 5 groups of 5 shots each they will all vary from 1/2 MOA to 1MOA even if they are all the exact same load. I dont think my barrel is accurate enough for me to tune the minor details like that. I have guns that will almost literally shoot a 1/2 minute 5 shot group every time and this gun is just not one of them. It also cost me half the price of those other guns, and it does consistently shoot sub MOA.

              I would focus on finding a charge weight and bullet combo that consistently shoots and go from there. XBR8202 seems to fire really well in every BHW barrel I have heard of. Most guys find accuracy in the 27.9-28.5 grain range with the 123 AMAX. Start low and work your way up though, 28.5 grains is the max.

              Comment

              • 1911man
                Warrior
                • May 2015
                • 482

                #8
                Originally posted by Cornbread View Post
                I would definitely try a different powder. From what I gather 8208 is very popular. I may try some AR comp. There is not much data for it though. I would usually adjust the powder charge first but in this case I had a velocity where I wanted to be. I will probally adjust the charge weight a bit at the 2.28 coal and see what happens. My goal is to find a consistent sub moa load for both bullets at 2450-2500 fps.
                For AR Comp I started at 27.0 grains and worked my way up. I found an accurate load at 28.0 and 28.3 grains with zero pressure signs with the 123 Amax. I tried the same combo with the SSTs and did not get quite as good of results. I have only fired 15 shots of SST though so my testing with it is far from over. I had one group at .6xx" range and the other to were 1.5" +. Could be that I was shooting with a pretty hot barrel at that point though. Accuracy has been very consistent with my 28.3 grain Amax load and the velocity is in the 2480 fps range in the one 5 shot string I shot over the Chrono. i plan on doing my long range testing with it in the near future.

                Comment

                • NugginFutz
                  Chieftain
                  • Aug 2013
                  • 2622

                  #9
                  Originally posted by BluntForceTrauma View Post
                  Great report, and glad your careful work paid off!

                  There's a theory out there that tuning loads for velocity is for, well, velocity, but that tuning seating depth is for accuracy. I don't know enough about it, but it seems your particular experience here bears that out.
                  I don't know if that is specifically true, BFT, as I think both play a part. I have found that I can make seating depth changes that will open or tighten any load I have, and I've found some loads just won't group well, no matter the seating depth.

                  My load workup philosophy is this: Find the seating depth that gives you the best accuracy FIRST, choosing a median powder charge to test with. THEN go looking for a charge weight. This has what I perceive as two main benefits. One - All charges are starting the bullet from the same "happy place". Bullet jump is ostensibly optimized. Two - each load evaluated will have a constant case volume, which avoids variations in velocity from the resultant pressure changes.

                  Do this for any new bullet you try, and I believe it can let you find their true potential more quickly.
                  If it's true that we are here to help others, then what exactly are the others here for?

                  Comment

                  • BluntForceTrauma
                    Administrator
                    • Feb 2011
                    • 3897

                    #10
                    NF, good advice, makes sense!
                    :: 6.5 GRENDEL Deer and Targets :: 6mmARC Targets and Varmints and Deer :: 22 ARC Varmints and Targets

                    :: I Drank the Water :: Revelation 21:6 ::

                    Comment

                    • Cornbread
                      Warrior
                      • Dec 2015
                      • 288

                      #11
                      Originally posted by NugginFutz View Post
                      I don't know if that is specifically true, BFT, as I think both play a part. I have found that I can make seating depth changes that will open or tighten any load I have, and I've found some loads just won't group well, no matter the seating depth.

                      My load workup philosophy is this: Find the seating depth that gives you the best accuracy FIRST, choosing a median powder charge to test with. THEN go looking for a charge weight. This has what I perceive as two main benefits. One - All charges are starting the bullet from the same "happy place". Bullet jump is ostensibly optimized. Two - each load evaluated will have a constant case volume, which avoids variations in velocity from the resultant pressure changes.

                      Do this for any new bullet you try, and I believe it can let you find their true potential more quickly.
                      What I typically do is run a ladder test at 100-200 yds depending on the rifle. For a long range target gun you can even go 300 yds or more. One round at each charge weight across a chrono to check velocity and pressure. With a non match barrel in a hunting rifle you can usually see the vertical node clusters at 100 yds. I'll pick the accuracy node close to max charge and go from there. This can really save bullets and powder compared to the load 3-5 rds at each charge method. In 8-10 rds I can usually find a good node. I mean if 3 bullets from a variance of 1 to 1.5 grains shoots sub moa the middle load shoulde be sub moa. You do need a solid shooting platform to eliminate as much shooter error as possible.

                      Comment

                      • holmess89
                        Unwashed
                        • May 2015
                        • 7

                        #12
                        Originally posted by Cornbread View Post
                        I would definitely try a different powder. From what I gather 8208 is very popular. I may try some AR comp. There is not much data for it though. I would usually adjust the powder charge first but in this case I had a velocity where I wanted to be. I will probally adjust the charge weight a bit at the 2.28 coal and see what happens. My goal is to find a consistent sub moa load for both bullets at 2450-2500 fps.
                        I might have to try AR Comp, I have seen it mentioned a couple of times with good results. My current third powder is TAC, and I think I can already conclude it is a bust. I have also heard that CFE 223 is a good powder in the Grendel, any experience with it?

                        Comment

                        • 6.5 Grendel
                          Warrior
                          • Nov 2015
                          • 199

                          #13
                          I have a 20" 264 lbc BHW barrel and it really seems to like 123 gr SST's @ 2.270 to 2.276 with 31.6 to 32.3 grs of Leverevelotion powder. Velocity with the 32.3 is 2610 fps on average and 6 shot groups have been bug holes to no more than an inch on my bad days.
                          "One Good Shot Is All I Need."

                          Comment

                          • Cornbread
                            Warrior
                            • Dec 2015
                            • 288

                            #14
                            I need to try some leverevolution. Should work good with the heavier bullets.

                            Comment

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