6mm AR loads in 6.5 Grendel

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts
  • lwminton
    Warrior
    • Nov 2014
    • 143

    6mm AR loads in 6.5 Grendel

    If I have a load that works well in 6 mm AR would it work in the Grendel - same powder charge same weight bullet?

    I understand that same weight bullets are different lengths which should matter some I think.

    If I could find a 6.5 mm bullet of the same weight and length (not sure if possible) as a 6mm, why wouldn't that work?

    The reason I ask is that I have 0.5 minute loads in the 6mm using H4895 and RE 15 but those powders are not talked about much here.
  • SG4247
    Warrior
    • Aug 2013
    • 497

    #2
    I would say generally no, the loading doesn't seem to translate like you would think it should.

    My best powders for the 6AR are, H4895, Benchmark, 8208 and RL15.

    Tried many of the more popular Grendel powders CFE, Varget, N133 and others in the 6AR, with below average results.

    I think for me, the lack of easy powder translation between Grendel and 6AR is due to lack of really good 6.5 diameter bullets in the 105 grain weight class for Grendel, like the 6 mm has now.

    My 6AR shoots all the 105 and 108 grain bullets regardless of manufacturer, very very well. Some even share the exact same charge.

    Go figure..
    NRA F-Class Mid Range High Master

    Comment

    • lwminton
      Warrior
      • Nov 2014
      • 143

      #3
      Have you tried all copper bullets - they are longer, no?

      Comment

      • SG4247
        Warrior
        • Aug 2013
        • 497

        #4
        In Grendel? No.

        I have really struggled in general, to find a good 100-110 target bullet for 6.5 Grendel.

        The solids are definitely different than jacketed, and the 107SMK doesn't like any of my guns.

        Bullet OAL is a problem for 6.5 Grendel. There just isn't much to choose from in 100 grain class except for a few hunting bullets.

        Haven't yet tried any of the shorter flat base bullets yet either.

        My favorite BT was the 6.5 mm 100 grain Berger, which is now discontinued.

        If you have a copper in the 100-110 weight range - from Bart or someone, I'd be willing to try them.

        What bullet were you considering?
        NRA F-Class Mid Range High Master

        Comment

        • Bwild97
          Warrior
          • Jan 2015
          • 217

          #5
          Originally posted by lwminton View Post
          If I have a load that works well in 6 mm AR would it work in the Grendel - same powder charge same weight bullet?

          I understand that same weight bullets are different lengths which should matter some I think.

          If I could find a 6.5 mm bullet of the same weight and length (not sure if possible) as a 6mm, why wouldn't that work?

          The reason I ask is that I have 0.5 minute loads in the 6mm using H4895 and RE 15 but those powders are not talked about much here.
          Simple answer is no, because; smaller diameter, shorter projectile, equal case capacity cartridge is going to react to powder burn rates differently.
          Hypothetically speaking, RL15 in the 6mmAR is = to CFE in the Grendel. IMR4895 in the 6mmAR is = to XBR in the Grendel. I hope that helps that skew make a little bit of sense.

          So will you get equal accuracy? It's possible, but equal velocity, no.

          Comment

          • lwminton
            Warrior
            • Nov 2014
            • 143

            #6
            Originally posted by SG4247 View Post
            In Grendel? No.

            I have really struggled in general, to find a good 100-110 target bullet for 6.5 Grendel.

            The solids are definitely different than jacketed, and the 107SMK doesn't like any of my guns.

            Bullet OAL is a problem for 6.5 Grendel. There just isn't much to choose from in 100 grain class except for a few hunting bullets.

            Haven't yet tried any of the shorter flat base bullets yet either.

            My favorite BT was the 6.5 mm 100 grain Berger, which is now discontinued.

            If you have a copper in the 100-110 weight range - from Bart or someone, I'd be willing to try them.

            What bullet were you considering?
            I shoot the 100 gr Bergers now (I have about 1,000) with 28.4 H4895 and have also shot the 106s with 28.5 (long ago). Had some success with the 106 VLD 5 jammed .005 with 28.6 RE 15.

            Comment

            • Rainman
              Bloodstained
              • May 2015
              • 87

              #7
              When I started loading 6.5 Grendel I rounded up all the odds and ends 6.5 bullets I had used in my Kimber .260 excluding 140s. This included a dozen or so each 100 and 120 grain Nosler hollow point match bullets. Using the load data for most accurate load from Nosler's online resource, both were very accurate delivering around .5 MOA. Since I have achieved equal or better accuracty with Sierra 107 and 120 MKs and have not been to the Nosler store in Bend, OR to replenish my supply of their bullets, many of which are available as blems/seconds at discounted prices, I have not done any additional testing with them. The Nosler 100s are certainly worth a try.

              Comment

              • Klem
                Chieftain
                • Aug 2013
                • 3507

                #8
                Unfortunately not...the volume of the barrels are different between 6mm and 6.5.

                This means you are still going to get a different time/pressure curve if using the same powder and weight of bullet.

                Comment

                • lwminton
                  Warrior
                  • Nov 2014
                  • 143

                  #9
                  Originally posted by Klem View Post
                  Unfortunately not...the volume of the barrels are different between 6mm and 6.5.

                  This means you are still going to get a different time/pressure curve if using the same powder and weight of bullet.
                  My recollection is that seating depth affects the pressure curve some (true?) so the barrel volume would be many, many times that effect.

                  No wonder.

                  Comment

                  • Klem
                    Chieftain
                    • Aug 2013
                    • 3507

                    #10
                    I imagine so... we know that varying the seating depth influences the pressure curve also.

                    I don't have experience with 6mmAR so please bear with me. I understand shooters use Grendel brass necked down to 6mm. So we are talking about the same case volume of around 36gns or water.

                    Same case volume
                    Same primer
                    Same weight of bullet

                    Seating depths are going to be difficult to keep similar heret because equal weighted 6mm and 6.5mm bullets are going to have different lengths/profiles.

                    Not having Quickload in front of me we still know the larger volume 6.5 barrel is going to permit the pressure to drop quicker. By the time the bullet passes the 6.5 gas port (assuming the port is at same length along the two barrels) you might need to open the port a little to get the same cycling pressure as the 6mm.

                    I read on the 6AR site shooters using the same powders as 6.5Gr so there's a good chance that the different barrel volumes in your hypothetical won't be enough to require a different powder. The muzzle velocities and time/pressure curve (for safety) for same length of barrel will be different however.

                    Comment

                    • lwminton
                      Warrior
                      • Nov 2014
                      • 143

                      #11
                      Originally posted by Klem View Post
                      I imagine so... we know that varying the seating depth influences the pressure curve also.

                      I don't have experience with 6mmAR so please bear with me. I understand shooters use Grendel brass necked down to 6mm. So we are talking about the same case volume of around 36gns or water.

                      Same case volume
                      Same primer
                      Same weight of bullet

                      Seating depths are going to be difficult to keep similar heret because equal weighted 6mm and 6.5mm bullets are going to have different lengths/profiles.

                      Not having Quickload in front of me we still know the larger volume 6.5 barrel is going to permit the pressure to drop quicker. By the time the bullet passes the 6.5 gas port (assuming the port is at same length along the two barrels) you might need to open the port a little to get the same cycling pressure as the 6mm.

                      I read on the 6AR site shooters using the same powders as 6.5Gr so there's a good chance that the different barrel volumes in your hypothetical won't be enough to require a different powder. The muzzle velocities and time/pressure curve (for safety) for same length of barrel will be different however.
                      A member of my pistol club is a WW 2 veteran. He lugged a machine gun across Europe and survived it. He also shoots competitive rifle and used to talk about how in his days they just kept hunting around for loads that worked. They didn't have computers - they just loaded and guessed and shot until one worked. The variables you describe reminded me of him. Ballistics is complicated. Watching him shoot rapid fire revolver single action was a thing to behold.

                      Comment

                      Working...
                      X