Went to range with IMR 8208 XBR with 123 AMAX and 107 Sierra.

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  • Went to range with IMR 8208 XBR with 123 AMAX and 107 Sierra.

    Shot with chronograph to test speed with 28 " barrel. All 5 shot groups.

    Factory load 2660 fps. 123 AMAX
    27.5 gr 8208 2560 fps "
    28.0 gr 8208 2590 fps "
    28.5 gr 8208 2650 fps "

    28.5 gr 8208 2760 fps 107 Sierra
    28.9 gr 8208 2790 fps "
    29.3 gr 8208 2815 fps '

    Did not find what I would consider an accurate load for 123 AMAX, all were around an inch or less at 100 yrds.

    The 107 Sierra was way better expecially with 28.5 gr. 8208. Was getting bullet holes touching with some in same holes with 5 shot groups. The higher loads were like the 123 AMAX.

    Will now test with Leverevolution to see if I can get better results with 123 AMAX.

  • #2
    Thanks for the data brickcues!

    Comment

    • CoolBarrelBill

      #3
      28" barrel am I reading that right?

      Comment

      • bwaites
        Moderator
        • Mar 2011
        • 4445

        #4
        Originally posted by CoolBarrelBill View Post
        28" barrel am I reading that right?
        Some of us have to compensate!!

        Comment


        • #5
          Originally posted by bwaites View Post
          some of us have to compensate!!
          lol

          Comment


          • #6
            I would suggest you try a few more loads. .5gr is too wide a range. There may be a sweet spot in between your loads. The a max bullet loads I tried had a very narrow sweet spot. .2gr up or down was out of the accuracy node. I did get slightly better results with leverevolution though. The accurate load range was still very narrow, though.

            Comment

            • bwaites
              Moderator
              • Mar 2011
              • 4445

              #7
              Originally posted by oxn316 View Post
              lol
              I really enjoy my 28" GSR!!

              Comment


              • #8
                Originally posted by CoolBarrelBill View Post
                28" barrel am I reading that right?
                Yep, special order thru Krieger.

                Comment


                • #9
                  Originally posted by mlmiller1 View Post
                  I would suggest you try a few more loads. .5gr is too wide a range. There may be a sweet spot in between your loads. The a max bullet loads I tried had a very narrow sweet spot. .2gr up or down was out of the accuracy node. I did get slightly better results with leverevolution though. The accurate load range was still very narrow, though.
                  I will try with the Leverevolution, I would think it would work better with the longer barrel to use a slower powder. Should allow lower cup pressure and still hold the fps. The 107 Sierra MK did like the 8208 at 28.5 gr, may try either side of that at .2 grs.

                  Comment


                  • #10
                    exspecially, it's not a word but it's spelled like one and with the same audacity as all the correctly formed words but its mere presence in the current form immediately takes any credibility the balance of the correctly built spellings and interesting content might have constructed for you. You mite wunt to axe a dickshinery abowt the spellinz.

                    Sorry, had to pick on him for that. Looks like he corrected the spelling of every word but that one.


                    Now then, nice data but I'd get away from even bothering to develop loads at .5gn increments. I've done a ton of load development in my life and found that it's only ever worthwhile to do .2gn increments at the beginning. Sure it makes you make a ton more loads your first day but you get closer to the sweet spot earlier in the process. I've also started to expect little more than MOA from the Amax's, at least from my gun.

                    Comment

                    • Glockzilla

                      #11
                      Krieger barrels are the way to go!
                      brickcues, what C.O.L do you have on the MK 107?

                      Comment


                      • #12
                        Originally posted by Glockzilla View Post
                        Krieger barrels are the way to go!
                        I agree, did you get Krieger to chamber the barrel or???
                        Details on the Barrel please (chamber profile etc) Looking at redoing a barrel.

                        On Topic the data is Great gives me a start point on the Powder thanks for the heads up

                        Comment


                        • #13
                          Loaded to 2.26 on the 107's which was about .02 short of the lands.

                          I had Krieger chamber the barrel in 264 LBC AR as I had purchased the reamer and go gage from Pacific Tool and sent to Krieger. After firing I noticed that the brass was .300 at the neck. I then measured the reamer which also showed .300. I do not know what I have as the 264 LBC AR was supposed to be .295 at the neck. Is the reamer a Grendel reamer that is mismarked or do I have a 264 LBC AR reamer that was cut wrong at the neck? I feel it is closer to the Grendel than the 264 LBC AR.

                          Comment


                          • #14
                            Up date on IMR 8208 and 123 AMAX. Found out that 123 AMAX likes to be loaded with .010 jump. On my original test I just loaded to magazine length and did no check to see where the bullet was. After I loaded and ejected a shell with out firing I noticed small scratches on the bullet. Bought a comparator and checked. Found that I was loading .015 into the lands. Reseated with .010 jump and 28.0 gr 8208 produced a 5 shot group of less than .750 at 200 yrds.

                            Tried the Leverevolution from 30 to 31 gr. in .2 gr increments. At 200 yrds the best group was about 2 in. Not very good with the 123 AMAX and .010 jump. The powder is also real dirty not as clean as 8208. I might try Hoots AR-COMP next and see how it does.

                            Comment


                            • #15
                              Alliant powder has a narrow window

                              Mlmiller is right about moving up in .2 grain increments when using Alliant powder. If you have access to reloder 15 try 29.4gr with a 2.255
                              Col for the 123amax. A 28" barrel can take advantage of a slow powder.
                              Alliant says ar-comp is a reformulated reloder 15. That load gives me
                              2507fps out of a 24" barrel with a .5" 5 shot group at 100 yds. My fired cases measure .294" at the neck.
                              Rich

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