Barrel Twist vs. Bullet Weight

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  • Barrel Twist vs. Bullet Weight

    I am a new 6.5 Grendel enthusiast. I'm now pretty familiar with the twist/performance effect vs. bullet weight with .223. Can someone fill me in on this science for the Grendel? I have a 1 in 8 and I thought I would like to work on loads for the 120 & 140 Hornady AMax in a 24" Pac-Nor barrel/AA upper receiver & bolt group. I'm looking for max accuracy at max range. Guide me.
    Dinger
  • bwaites
    Moderator
    • Mar 2011
    • 4445

    #2
    The 8 twist will stabilize just about any of the bullets suitable for the Grendel without issues, including the 140's. However...weights above 123 really push the cartridge. While some people have had success with the 129's and 130's, most think that the 110-123 range is ideal.

    The 120 AMAX is not the best choice, its got a blunt ogive in comparison to the 123 AMAX which is specifically engineered for the Grendel. That 123 bullet shoots REALLY well in almost every Grendel that I've heard about. It's a "go to" bullet for people having problems finding accuracy.

    For really long range stuff, beyond 600 meters, most people find the 108 and 123 Lapua Scenars to shoot the best. They are the same bullet profile, differing only in 15 grains of weight.

    All that said, my best groups, .25 5 shot groups at 100 yards, were all either 100 or 120 grain Nosler BT's over BLC2, a powder which burns very dirty for me. I shot them well out to 700 yards, but never tried them at longer range, never having the opportunity.

    I'll be the first to admit that I did not test the Lapuas anywhere near as extensively as I did the Noslers, since I had no where local to buy Lapuas and the Noslers shot so well!

    Bill

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    • #3
      Bill;

      I'm just breaking into the 6.5G, having just finished assembling a 24" 1:9 barreled rig and my particular interest was also in the Nosler BTs. I'm no stranger to reloading and I'm at that point in a new caliber where I'm in the information sponge mode. Other folks more knowledgeable than me have advised using powders 12 or more steps faster than BL-C(2). You've been around the block. Elaborate on how to get all the energy out of slower powders. I always like to come in light, slow and work up on a new caliber.

      Thanks,

      Hoot

      Comment


      • #4
        So, with the 123 Lapua and BL-C(2) where do you seat the bullet and/or what is your C.O.A.L.?
        Dinger

        Comment

        • bwaites
          Moderator
          • Mar 2011
          • 4445

          #5
          Originally posted by Dinger View Post
          So, with the 123 Lapua and BL-C(2) where do you seat the bullet and/or what is your C.O.A.L.?
          Dinger
          I generally seat everything to max mag length, unless I intend to shoot single load for long range competitions. So the Lapuas are set at 2.26.

          Bill

          Comment

          • bwaites
            Moderator
            • Mar 2011
            • 4445

            #6
            Originally posted by Hoot View Post
            Bill;

            I'm just breaking into the 6.5G, having just finished assembling a 24" 1:9 barreled rig and my particular interest was also in the Nosler BTs. I'm no stranger to reloading and I'm at that point in a new caliber where I'm in the information sponge mode. Other folks more knowledgeable than me have advised using powders 12 or more steps faster than BL-C(2). You've been around the block. Elaborate on how to get all the energy out of slower powders. I always like to come in light, slow and work up on a new caliber.

            Thanks,

            Hoot
            Hoot, the BLC2 is too slow for the 100 grain bullet, at least if it is going to be shot at extended range, at least theoretically! But like your sig line says, "In Practice, there is."

            I don't like it, its really dirty, and I now use XTerminator with those bullets. I lost a tiny bit of accuracy, picked up a little bit of velocity, and in the end it was a push, except that it runs much cleaner. I suspect that part of the reason its so dirty is that its really a little slow for the light bullets.

            At 120 grain bullets and the 123's, though, its very close to Alexanders factory powder velocities, in fact about as close as you can get. Its still dirtier than I like, but better suited to that weight. Accurate 2520 and Ram TAC might be a hair faster, but 2520 is more temp sensitive to me, (I shoot when its anywhere from 20-110 degrees in the shade). Others have suggested the same thing, so I don't think its all me.

            However, I load very little BLC2 now, and mostly use TAC and XTerminator. They run cleaner and are very close to as accurate. Since I didn't start using them until my barrel had lots of round down it, I can't be 100% sure it isn't some barrel and some powder in the difference.

            I've tried the new 8208, but not in the 108 Lapuas yet, and I've heard some good things, so I'll probably give that a try.

            Bill

            Comment


            • #7
              Hey Bill any chance we could get some of the old reloading info back on the forum. Any new stuff would be greatly appreciated. I am going to post on SnipersHide and let people know the site is back up and running. I think alot of guys gave up on the site ever coming back.

              Comment

              • cornholio1

                #8
                I have had very good luck with BLC2. Very accurate with Speer Hotcors. Mines an AA barrel. Any whoot, Bwaites, we should have a sticky post about trouble some bullets. The troubles we have had should be documented, so people don't waste so much time like I did trying to find an answer.

                I'd like to add 95 gr Vmax to the troublesome list. You can use it but seat it 2.15OAL!
                Last edited by Guest; 03-08-2011, 05:29 PM.

                Comment


                • #9
                  I'll second what bw says about TAC, X-term, and 2520. Some of the faster IMRs work well with the Nosler 100gr. BTs.

                  Comment

                  • bwaites
                    Moderator
                    • Mar 2011
                    • 4445

                    #10
                    Originally posted by rkflorey View Post
                    Hey Bill any chance we could get some of the old reloading info back on the forum. Any new stuff would be greatly appreciated. I am going to post on SnipersHide and let people know the site is back up and running. I think alot of guys gave up on the site ever coming back.
                    Grendelizer is working on it, but ?

                    I'm hoping that the really cool list that was up reappears soon from whoever it was that created it!!

                    Comment


                    • #11
                      It's my first Chorny on my 6.5 Grendel. Weather 58 deg. F., wind 7 to 9 mpg, and sunny. I was shooting north and wind was coming from the N NE. It opened the groups up a litte.

                      My reload data :

                      Case Lapua (new case)
                      Primer Wolf SRM
                      Powder Varget 28.5 gr. Hodgdon
                      Bullet 123 gr. A-max Hornady
                      COL 2.260 of an inch
                      Crimp Light

                      My Chorny data :

                      Ten Shot String
                      Max fps 2493.56
                      Low fps 2475.69
                      Ave. fps 2482.84
                      Spread 19.87 fps
                      Std. Dev. 7.5

                      Group size
                      Two 5 shot groups
                      Group 1 1.225 MOA
                      Group 2 0.785 MOA
                      Not bad for a windy day.

                      This was a max load, the reloading data was from US Army, Radford Arsenal, Radford Va. 24143.

                      My 6.5 Grendel AR has a 24" SS free floated barrel with a 1 in 7.5 twist and a PRI adjustable gass block, Shrewd muzzel brake, Mcfarland bolt gas rings, Tubb's carrier weight system, and Tubb's flat-wire buffer spring. The Upper is a DPMS high rider competition upper receiver. It has a AR15 lower with a Jewell trigger and rifle stock.

                      Mike

                      Comment

                      • CoolBarrelBill

                        #12
                        Has anybody tried H335 with the Nosler 100 gr BT? How well did it work?

                        Comment


                        • #13
                          [QUOTE=CoolBarrelBill;131]Has anybody tried H335 with the Nosler 100 gr BT? How well did it work?[/QUOTE

                          Worked extremely well with a chrome lned barrel.

                          Comment

                          • VASCAR2
                            Chieftain
                            • Mar 2011
                            • 6219

                            #14
                            Originally posted by CoolBarrelBill View Post
                            Has anybody tried H335 with the Nosler 100 gr BT? How well did it work?
                            I loaded some Nosler 100 grain BT with 28.0, 28.5 and 29.0 grains of H335 with Remington small rifle primers in Hornady cases OAL 2.220. None of the loads showed any pressure and functioned 100% in my rifle with about 200 rounds down the tube. The 29.0 H335 load was the most accurate and pleasant to shoot out of my J&T 16" upper. Group was right at 1 inch at 100 yards. I'm going to load more of these and hopefully chronograph all my loads as soon as the weather breaks. I have also loaded several different bullets with TAC and it looks very promising as a powder.
                            Last edited by VASCAR2; 03-09-2011, 09:16 PM.

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