,264 LBC vs. 6.5 Grendel chambering and bullet seating depth

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  • Rainman
    Bloodstained
    • May 2015
    • 87

    ,264 LBC vs. 6.5 Grendel chambering and bullet seating depth

    Is there a material difference in throat lengths or dimensions between these two chambers? I have an 18" BHW with LBC chamber. Working up loads with Berger 130 Target VLDs I seated to normal OAL and the bolt would not go fully into battery. Since I was not at max charges I reseated the bullets to reduce cartridge OAL by about two thousandths and that solved the problem. There were no marks on the bullets so they were not hitting the rifling. I mostly shoot 107-123 grain bullets but want to shoot steel at 1100 yards within my scopes elevation limits (SWFA SS 3-15) so am working up loads for Hornady 129 SSTs and the 130 Bergers. Since my twist rate is 1 in 9", slower than Berger's recommended maximum rate for this bullet, I was also pleasantly surpised with 100 yard accuracy. My lighweight upper will be with BHW's 1:8" twist rate.
  • LR1955
    Super Moderator
    • Mar 2011
    • 3355

    #2
    Originally posted by Rainman View Post
    Is there a material difference in throat lengths or dimensions between these two chambers? I have an 18" BHW with LBC chamber. Working up loads with Berger 130 Target VLDs I seated to normal OAL and the bolt would not go fully into battery. Since I was not at max charges I reseated the bullets to reduce cartridge OAL by about two thousandths and that solved the problem. There were no marks on the bullets so they were not hitting the rifling. I mostly shoot 107-123 grain bullets but want to shoot steel at 1100 yards within my scopes elevation limits (SWFA SS 3-15) so am working up loads for Hornady 129 SSTs and the 130 Bergers. Since my twist rate is 1 in 9", slower than Berger's recommended maximum rate for this bullet, I was also pleasantly surpised with 100 yard accuracy. My lighweight upper will be with BHW's 1:8" twist rate.
    RM:

    Yes, there is a difference between the throats so OAL may be different depending on the bullet you are using.

    This topic has been beaten to death on the forum already so run a search and do some digging and you will get the specs.

    Both use the same headspace. The LBC uses a more conventional throat and the AA Grendel a compound throat.

    You have done the right thing so it really doesn't make a difference anymore. You fit your overall length to your specific throat.

    If Berger says your twist rate is too slow for the bullet, it probably is. It may not show up at 100 as readily as 600 so try them at longer ranges and see.

    LR1955

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    • NugginFutz
      Chieftain
      • Aug 2013
      • 2622

      #3
      RM: Since the bullets are showing no marks, it seems to indicate your cases are the issue. In this regard, the most common issue is an improperly adjusted sizing die. If available, use a headspace gauge to determine if you're bumping the shoulders back enough to allow the bolt to close. With my BHW 264LBC, it works well when the shoulder has been bumped .003 - .005". The same goes for literally any gas operated 6.5 Grendel and its variant chambers.

      Welcome to the board, btw.
      Last edited by NugginFutz; 06-30-2015, 01:47 PM.
      If it's true that we are here to help others, then what exactly are the others here for?

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      • wfa17332
        Bloodstained
        • May 2015
        • 44

        #4
        Because of the nature of BHW "rifling", you are not going to see distinct marks on the bullet as can be found with Enfield rifled barrels. I have three BHW barrels (including a 264 LBC) and I can't see any marks on bullets I KNOW are jammed into the rifling.

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        • NugginFutz
          Chieftain
          • Aug 2013
          • 2622

          #5
          Originally posted by wfa17332 View Post
          Because of the nature of BHW "rifling", you are not going to see distinct marks on the bullet as can be found with Enfield rifled barrels. I have three BHW barrels (including a 264 LBC) and I can't see any marks on bullets I KNOW are jammed into the rifling.
          Good point, to be sure. All the BHW 264LBCs I've had any dealings with, though, had more freebore than a round loaded to mag length could use. When my BHW was new, 123 AMaxes seated at 2.260" still had about .040" jump. The 129 SSTs and 130 Bergers, on the other hand, might have an issue. Closing the bolt on a sized, but empty case will answer the question.
          If it's true that we are here to help others, then what exactly are the others here for?

          Comment

          • wfa17332
            Bloodstained
            • May 2015
            • 44

            #6
            Which is why I use nothing but ASC SS mags with the BHW 264 LBC - every little bit seems to help.

            All Sierra and Speer bullets I've tried easily fit into a standard mag.

            Comment

            • LR1955
              Super Moderator
              • Mar 2011
              • 3355

              #7
              Originally posted by NugginFutz View Post
              RM: Since the bullets are showing no marks, it seems to indicate your cases are the issue. In this regard, the most common issue is an improperly adjusted sizing die. If available, use a headspace gauge to determine if you're bumping the shoulders back enough to allow the bolt to close. With my BHW 264LBC, it works well when the shoulder has been bumped .003 - .005". The same goes for literally any gas operated 6.5 Grendel and its variant chambers.

              Welcome to the board, btw.
              NF:

              His brass is fine. He seated the bullet out too far. When he seated the bullet deeper into his case, the cartridge chambered without any problems.

              LR55

              Comment

              • Rainman
                Bloodstained
                • May 2015
                • 87

                #8
                I did initially have a problem with case sizing. However, I finally set my Hornady sizing die up with a feeler guage and .003 clearance which solved that problem and the 130 grain rounds I had a problem with were all checked in my Wilson chamber die so I figured it had to be a bullet length issue but wanted confirmation. The 1,100 yard range we have access to is about 300 miles away so we only get there two or three times each year and the steel is taken down during the summer due to fire hazzard. So it will be this fall before I can test loads for accuracy beyond 200 yards and try my hand at 1,100 yard steel. I have no great expectation for accuracy holding up much beyond 100 yards based on Bergers testing. So far the handloads I have settled on for various bullet weights from 107 to 123 grains all shoot MOA or sub MOA out to 400 yards on paper and nail steel out to almost 900 yards. I'm real happy with my BHW barrel but do want a second with a faster twist rate. Thanks for the input guys.

                Comment

                • NugginFutz
                  Chieftain
                  • Aug 2013
                  • 2622

                  #9
                  Originally posted by LR1955 View Post
                  NF:

                  His brass is fine. He seated the bullet out too far. When he seated the bullet deeper into his case, the cartridge chambered without any problems.

                  LR55
                  So sayeth the man who actually read the entire OP. I can't begin to count the number of times I have failed to do that. Apologies to the OP.
                  If it's true that we are here to help others, then what exactly are the others here for?

                  Comment

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