First Build Having Grouping Problems

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  • tintopfrog
    Unwashed
    • Jan 2017
    • 7

    First Build Having Grouping Problems

    Hi Everyone- New to the forum and wanted to get some insight from yall on the grouping issues I am having. I've always had bolt actions but thought it would be fun to have a precision hog/varmint gun on an AR platform and the Grendel seemed to be the best route. I bit the bullet and bought a brand new Lilja 319 18" SS fluted barrel as well as the Lilja bolt that they recommended. Scope is a Vortex HD gen II 4.5-27 x 56 mounted with Vortex precision rings torqued to specs along with Loctite. Also am running a silencerco Saker Suppressor. Everything else is pretty standard...IE Anderson upper receiver & lower, DPMS carrier, 15" Free Float Hand Guard, mid length gas system with standard gas block (non Adjustable).

    I took it to the range this weekend and was pretty disappointed in the outcome-shooting both the Hornady 123 A max as well as the Hornady Black 123 ELD match. I'd have a couple shots within a five shot group that would be same hole however it would start walking after that, probably out to 3-4 MOA or so at 100 yards. Had two buddies with me who are excellent shooters and were having the same issues. I was halfway expecting to have feeding issues since that seems to be one of the more common problems with new builds (especially with rookies such as myself building them!), but outside of a few slightly dented spent rounds, it fed just fine...

    also important to note is we were shooting out of a lead sled so we had plenty of stability in the rest. Any thoughts or things I should try?

    I appreciate the help in advance!
    Attached Files
  • Texas
    Chieftain
    • Jun 2016
    • 1230

    #2
    Take the suppressor off and retest!

    Comment

    • tintopfrog
      Unwashed
      • Jan 2017
      • 7

      #3
      ya I think I will try that this weekend as it was suggested on a couple other forums too. May try the direct thread route instead using the adapter that fits over the flash hider as well.

      thanks for the suggestion!

      Comment

      • hikfromstik
        Warrior
        • Oct 2016
        • 190

        #4
        Have you looked at the gas tube alignment ? I had to tweek mine after I had accuracy issues after assembly. Check to make sure it's free floating as good as possible, then check your gas key and see if the gas tube and key line up . Do this by taking the upper off , then turn it upside down and slide the bolt carrier forward and listen/feel for resistance. If you feel resistance then you should loosen your gas block slightly then move the tube until it aligns with the key . I hope this is the problem because I've read stories about flutes being cut too deep that cause barrel walking/stringing. Lilja is a very respectable barrel manufacturer, so I bet it's something little.

        Comment

        • tintopfrog
          Unwashed
          • Jan 2017
          • 7

          #5
          Ok awesome I'll definitely try that too! Ya my fear was that I spent all that money on the barrel and getting less than desireable results.... so like you said, hopefully it's something little like the gas system not being properly aligned.

          With yalls experience, what size groups do you think are realistic with the set up I have listed? I'd really like to get this thing to sub MOA.

          Thanks again for your help!

          Comment

          • The Profit Joseph Sith
            Warrior
            • Nov 2016
            • 596

            #6
            I dont think ive ever heard of a lilja not being sub moa. Their pretty good like you said. Although i see quite a few high end even precision sniper rifles with fluted barrels ive read that you can see them walk sometimes. The article said you can test this by mounting three lasers two receiver mounted and one on the barrel and as it heats up you can watch the barrel laser deviate off zero. Not by much and im sure its not true for all but some. Get scientific, control as many variables as possible and narrow it down. Try all cold bore shots even if the fluting is whats causing it that will help you determine if thats the cuase. Im newb myself so i hope this helps, and id be interested to hear the cause when you figure it out. Good luck! And welcome!

            P.s. i thought tiborsaurusrex did a good job explaining fluting in his sniper 101 video series on YT.
            Last edited by The Profit Joseph Sith; 01-24-2017, 01:57 PM.

            Comment

            • LRRPF52
              Super Moderator
              • Sep 2014
              • 8569

              #7
              Originally posted by Texas View Post
              Take the suppressor off and retest!
              This ^^^^.

              There aren't many cans on the market that will retain zero with heat, since hardly anyone has cracked the code on concentric cores.

              If you want minimal shift, look at Thunderbeast. There's a reason why they are what they are.

              Silencerco is still a great company that has done great things for the market by getting as many cans into people's hands as possible.

              NRA Basic, Pistol, Rifle, Shotgun, RSO

              CCW, CQM, DM, Long Range Rifle Instructor

              6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

              www.AR15buildbox.com

              Comment

              • rabiddawg
                Chieftain
                • Feb 2013
                • 1664

                #8
                My ar's don't fit in a leadsled properly. I have to twist/torque them to keep the crosshairs level.

                Ditch the leadsled and I bet your groups improve.
                Knowing everthing isnt as important as knowing where to find it.

                Mark Twain

                http://www.65grendel.com/forum/showt...2-Yd-Whitetail

                Comment

                • tintopfrog
                  Unwashed
                  • Jan 2017
                  • 7

                  #9
                  is there a certain amount of time that i should allow in between grouping shots that i should stick to? Do AR's create more heat with each shot than bolt guns do?

                  Comment

                  • tintopfrog
                    Unwashed
                    • Jan 2017
                    • 7

                    #10
                    Originally posted by rabiddawg View Post
                    My ar's don't fit in a leadsled properly. I have to twist/torque them to keep the crosshairs level.

                    Ditch the leadsled and I bet your groups improve.
                    good idea! i did notice the crosshairs not being quite even but assumed it may be just because the table wasnt perfectly level!

                    Comment

                    • tintopfrog
                      Unwashed
                      • Jan 2017
                      • 7

                      #11
                      I think it is fair to mention that I have a very standard AR trigger- which as we know isn't conducive to accurate shooting. anyone believe that I could have a big influence on 100 yard groups? and if so what triggers do yall recommend?

                      Comment

                      • Bigs28
                        Chieftain
                        • Feb 2016
                        • 1786

                        #12
                        I just got the larue mbt and i love it not to mention the price is very good. I did the i can wait cheaper price and got it in 3 weeks.

                        Comment

                        • tintopfrog
                          Unwashed
                          • Jan 2017
                          • 7

                          #13
                          Originally posted by Bigs28 View Post
                          I just got the larue mbt and i love it not to mention the price is very good. I did the i can wait cheaper price and got it in 3 weeks.
                          ok cool ill look into that one! do yall recommend the 2 stage or single? or is just personal preference?

                          Comment

                          • 1911man
                            Warrior
                            • May 2015
                            • 482

                            #14
                            Keep in mind he has described a shift of 3-4 MOA on each shot. That is not an issue of quality trigger or an unstable rest. Also, there are lead sleds designed to hold an AR so he could have one of those. Anytime you are experience a wide shot like that I would definitely think there is a mechanical issue such as scope, scope mount, barrel nut, etc. The suppressor is the first variable so I would eliminate that first.

                            Comment

                            • just_john
                              Chieftain
                              • Sep 2012
                              • 1565

                              #15
                              If the upper receiver is forged ( you did not give a build list ), did you true the barrel face to the bore and if there was any play to the seated barrel, did you use Loc-Tite to secure it? It is very possible that your barrel is moving in the receiver if these conditions were not addressed with a forged receiver. I only use forged as they are considerably stronger but have made it a practice to true and glue.

                              Comment

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