Help with 8208xbr & Amax

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  • NugginFutz
    Chieftain
    • Aug 2013
    • 2622

    #16
    Glad to see things are shaping up for you, outlaw.

    Just for information's sake, a few weeks back, a friend of mine and I were out shooting, and I noticed his target was showing serious key holing. After a consultation with the LGS, we decided to pull the flash hider and the problem went away. His was not an A2, but a fancy BCM job. Only thing we could figure was that a problem with concentricity might have been the culprit. He re-mounted the original flash hider, and now everything works just fine.

    So I guess the answer to your question about FH's is: "Yes - they can affect accuracy."
    If it's true that we are here to help others, then what exactly are the others here for?

    Comment

    • Drifter
      Chieftain
      • Mar 2011
      • 1662

      #17
      Originally posted by outlaw45 View Post
      After shooting my test loads I shot 3 more factory Hornady loads. They opened up quite a bit.


      So maybe a hot barrel is to blame? Temp was 87 degrees and I waited about 3-5 minutes between groups.
      It can sometimes take a few shots for a load to settle in when switching ammo. The next 3 shots with factory ammo might have been in the orange.

      Not all barrels behave the same. Shooting more helps to learn its likes and dislikes regarding ammo, hot barrel, cold bore, clean bore, etc.

      One good aspect is that your barrel seems to put the first few shots of factory A-max right where they belong with a cold clean bore. Nice shooting.
      Drifter

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      • outlaw45
        Warrior
        • Sep 2012
        • 104

        #18
        I'll try 27.8 to 28.2 again. Also extend C.O.L. to 2.250 or 2.260.

        Comment

        • NugginFutz
          Chieftain
          • Aug 2013
          • 2622

          #19
          I suspect you may know this, but when you seat longer, ensure you are not jamming or your pressures can spike. Mine likes it when seated with .010" of free bore.
          If it's true that we are here to help others, then what exactly are the others here for?

          Comment

          • LR1955
            Super Moderator
            • Mar 2011
            • 3355

            #20
            Originally posted by outlaw45 View Post
            I loaded these on a RCBS ChargeMaster.

            Then why do a lot of people claim that 28.5 grains of 8208xbr is the magic load that seems to work in every Grendel?
            http://www.65grendel.com/forum/showt...referred-Loads
            Scales drift minute to minute. Yours did but you won't notice it because there are other variables that will play a bigger role in accuracy than a change of .1 grain of powder. So, we tend to go with .3 grains.

            Why would guys go with 28 grains of 8208 and not think they are getting into tricky situations?

            Because they haven't sheared any bolt lugs yet.

            Let me add that I will go up to 28 gr of 8208 with 120's or 123's but won't go over. I trust 28 to work in all weather conditions I experience. I have gone up to 29 with 120's and will state flat out that it is too hot for that bullet weight. I have also shot a bunch of 120's with 28 1/2 and found them to be hot and won't go there when the temps get over 70 F. So, I settled on 28 being max. The additional powder did not improve performance in any manner so wasn't worth another bolt or brass wear.

            LR1955
            Last edited by LR1955; 08-21-2014, 02:23 PM.

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            • outlaw45
              Warrior
              • Sep 2012
              • 104

              #21
              I loaded up some more thinking one of these will be my final load. 27.8 and 28.0 of 8208 under 123gr Amax and I also loaded them longer at 2.260. Still using standard primers. Would magnum primers make a difference?

              Shot 28.0gr and the group on the left first. Seemed ok for the first 5 rounds but the second group opened up.


              27.8gr. Shot the group on the left first. The group on the right I adjusted the scope down. I thought the first group would be ok but there was no wind. It was 88 degrees and humid.


              These groups were shot with a dirty barrel. I think I will continue to reduce the loads and try to find a node that works. I am noticing ejector marks on the case head. Might go with 27.0 to 27.6 next.

              Any thoughts or suggestions?

              Comment

              • dmsims21
                Warrior
                • Nov 2012
                • 430

                #22
                Magnum primers would be worth trying. In addition to more boom, they have a harder cup, so they are less likely to slam fire in guns with free floating firing pins.

                I am not trying to be mean, but how is your shooting technique? Mine isn't very good. I grip and hold the rifle differently almost every shot.
                I am getting 0.9ish MOA groups (5 shots) out of my Lilja 319. That is pretty good, but my groups usually have a flier or two.
                My best load is 123 A-Max, 28.0gr 8208, 2.25" OAL, CCI450, Lapua brass. I am weighing every charge, because 8208 dumps +/- 0.3gr sometimes.
                My velocities are very consistent, so I am guessing that I am causing the fliers. I feel I could get consistent 3/4 MOA, if I could shoot.

                I have used different bag setups that are rock solid, but I end up fighting the natural point of aim. I don't have the patience to point the setup correctly at the target. This causes the recoil of the rifle to be inconsistent.
                I found that I shoot better off of a bipod and a rear squeeze bag. The reticule isn't as steady, but I hold the rifle much more consistently. I feel shooting off of a bipod is also better practice for hunting and the Zombiepocalypse.

                I would look at your velocity spread, shooting technique/setup, and make sure you don't have anything loose.
                You may also have a barrel that doesn't like to get hot.
                www.FriendsvillePrecision.com - AR15 Dry Fire Device

                Comment

                • lrgrendel
                  Warrior
                  • Jul 2013
                  • 662

                  #23
                  I am not an expert but IMR 8208 would never work for me in my AA 24". I got very frustrated. Bought 8 lbs...... Will probably try it in my 308.
                  AA 2520 works well for me with the same components you mentioned and also Varget but is a little slow depending on your application.

                  Comment

                  • SG4247
                    Warrior
                    • Aug 2013
                    • 497

                    #24
                    photo.jpg

                    This was the best load I found initially with the Lilja 20" 740 barrel.

                    My favorite 8208 loads for other Grendel rifles DID NOT shoot well in the Lilja Barrel.

                    I would suggest you attempt to get a good group with the factory SST ammo as shown, and then go back to load development.

                    Could be the shooter, the set up, the conditions, the rifle, etc...

                    Just get a good base line first.
                    NRA F-Class Mid Range High Master

                    Comment

                    • outlaw45
                      Warrior
                      • Sep 2012
                      • 104

                      #25
                      Yes I accept it could be me shooting that is the problem but on page 2 of this thread I posted a picture of a 3 shot group of factory Hornady 123 Amax that was 1/2". I've also shot a 5 shot group with the Hornady stuff that was just a little bigger that 1/2". I know the gun will shoot and that I'm capable of doing it. My reloads seem to be very inconsistent. That's why I'm still thinking it's my loads. I'm shooting off a stable bench, front rest and a rear bag. I dry fire before shooting to check natural point of aim. Maybe it like a clean barrel?

                      Comment

                      • SG4247
                        Warrior
                        • Aug 2013
                        • 497

                        #26
                        Understood, I saw the groups using 123 Amax. Not very many rounds fired of it is all.

                        I am just suggesting you increase the sample size of factory ammo in the Lilja barrel. Shoot a couple boxes of 123 Amax factory ammo on a Saturday, and see if the groups change significantly.

                        This way you know what the gun will do with temperature increases, shooter fatigue, etc.. by shooting a series of 5 shot groups on four targets, (1 box) over a short period of time with the same load.

                        You will probably be surprised by the results.

                        So, when my reloads do not shoot well, I immediately go back to my known load and shoot it, knowing what to expect.

                        I've seen dirty barrels. loose muzzle brakes, inconsistent powder load, Wrong COAL, etc.. all be a factor in my evaluations of reloads, and sometimes - it is just me as a shooter.
                        NRA F-Class Mid Range High Master

                        Comment

                        • LR1955
                          Super Moderator
                          • Mar 2011
                          • 3355

                          #27
                          Originally posted by outlaw45 View Post
                          Yes I accept it could be me shooting that is the problem but on page 2 of this thread I posted a picture of a 3 shot group of factory Hornady 123 Amax that was 1/2". I've also shot a 5 shot group with the Hornady stuff that was just a little bigger that 1/2". I know the gun will shoot and that I'm capable of doing it. My reloads seem to be very inconsistent. That's why I'm still thinking it's my loads. I'm shooting off a stable bench, front rest and a rear bag. I dry fire before shooting to check natural point of aim. Maybe it like a clean barrel?
                          If it likes a clean barrel, your barrel is the problem since the only time it is clean is on the first shot.

                          Try this if you want. Shoot faster. Get your stuff set up and dry fire a couple of times. Use a very solid position.

                          Load five and shoot them in fifteen to twenty seconds.

                          As you are shooting focus your attention on holding your sight picture through the entire shot. As if the rifle were locked into a vice. Do not become sidetracked by trying to see your bullet holes. Focus on holding your sight picture for the entire string. Your string may not be in one of those black squares but I bet you will tighten up the groups providing they can be tighter. I think they can with any of the loads you are testing.

                          LR55

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                          • outlaw45
                            Warrior
                            • Sep 2012
                            • 104

                            #28
                            Both good advice.

                            Comment

                            • outlaw45
                              Warrior
                              • Sep 2012
                              • 104

                              #29
                              Still working on my pet load. Again, reading through the preferred grendel loads thread a lot of people have success with 28.5gr of 8208xbr. You all have told me to watch for pressure signs, can you give me ideas of what I should be looking for, velocity spikes, ejector swipes, the direction cases eject?

                              I've been using standard primers, by switching to magnum primers how would that affect pressure? Can use the same load and just switch primers (I know the right answer is to work up the load again)?

                              Comment

                              • Dogue
                                Warrior
                                • Mar 2011
                                • 415

                                #30
                                If you're playing at the edge you really need to use a chrony...by the time you see pressure signs on the case you're probably way over.

                                And yes, rework when changing to magnum, especially when at max loads.
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