Grendel vs 308

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  • SHORT-N-SASSY
    Warrior
    • Apr 2013
    • 629

    #16
    Originally posted by rwh
    I was confused by the way this thread started out as a comparison of grendel in AR15 vs 308 in an AR10 followed by a comparison of a 308 bolt gun shooting hand loads to a grendel shooting factory ammunition. I was also thrown by the big difference between the trajectory I got from Sierra Infinity Suite compared to what bigbear_98 was getting from the JBM ballistics engine. I think it is time to retire Sierra Infinity as JBM confirms what I've suspected all along, which is that getting a grendel to shoot to 1000 yards, while possible, is roughly equivalent to trying to get an M1A to shoot out to 1000 yards. Both can do it, but neither is ideal.

    I've been playing with the idea of an AR10 build, but I would probably not go with a 308 in an AR10 either. I was thinking 260 remington or 6.5x47 lapua. I would be interested if anyone has any data on how an AR10 does with hot loads. What parts on the AR10 are going to start breaking as I begin pushing loads up close to max for the cartridge. Is the AR10 really able to push the same kinds of loads one would use in a bolt gun?

    Very nice shooting.
    Let's not count the 6.5mm Grendel out, as a 1,000-yard contender:

    http://www.youtube.com/watch?v=HbYlKXPbH0k (Jump to 1:49)

    Hi All, Just thought I'd let you know how the Grendel performed at 600 and 1,000 yards the other day. The North State Shooting Club in Butner, NC (http://www.northstateshootingclub.com/newindex.htm) had a warmup match Friday 6/15/12 for the NRA Long Range Regional, and matches Saturday and Sunday. The NSSC has a great


    So I was out shooting with my BIL and his FIL. Some guys pulled up and said they would be shooting Glocks out to 1200yds that would put the trajectory over our heads with just a slight wind gust, but not to worry, the guy teaching them was highly experienced and it would be ok, he trains SWAT teams, etc. We expressed the


    Then, there's the recoil factor: effectively, nonextant.

    Comment

    • LRRPF52
      Super Moderator
      • Sep 2014
      • 8569

      #17
      Yes, I also don't normally put a lot of faith into ballistics programs, but I have learned that if you have solid atmospheric data, and true muzzle velocity data, you can be dead-on at ranges that were previously "walked into".

      At the altitudes where I shoot at, I found that the 123gr A-MAX factory load is still supersonic out to 1318yds for me in 80 deg F, at 4400ft elev. 14.4 mils was what my program told me I would need for 1200yds, and the first shot literally barely missed the left edge, which then became my aiming point in the reticle for the next four rounds. That opened my eyes up to what this thing could do.

      As to .308 AR's, I doubt I'll ever own one again, and I've had several of them, 5 total, 3 chambered in .308, and 2 chambered in .260 Rem. In the process of building more Grendel's as we speak. The only AR10 I'm looking at now is the Freedom Group GII, but it will have to be re-barreled from the start in .260 Rem., with a bunch of custom work.

      They're still working on the bolt and firing pin hole diameters for the GII, since it exhibits the same problems other .080" AR10's. The elongated pressure curves of long bearing surface pills with slow powders hits the AR10 gas port hard, and also burns through primers if things aren't set up right.

      SG4247 sent me a firing pin upgrade for my .080" firing pin hole AR10 in .260 Rem., which has been working well since I installed it. I push 129gr and 130gr class bullets at 2800fps from a 22" barrel, but it's a reloader's cartridge only with that rifle. No way would I shoot factory .260 Rem. from it. I have to size all my brass before loading too, so you'll understand why my Grendel's go out to play more.
      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

      • sneaky one
        Chieftain
        • Mar 2011
        • 3077

        #18
        Bigbear98, As to -on game performance between the .308 , & the Grrr.= I have owned both, shot whitetail w/ both. The ballistics speak well of the expected on game results. The Grendel is - basically , a 2/3rds of performance on game kills, as compared to .308.

        Always wanted a .260 since it's inception, in the 90's. I'm glad that I waited a decade , for my first 6.5 rifle tho.. The mighty Grrr rocks.

        Could not be happier , here. I have since sold the .308- to my fave BIL. He's also a happy guy.

        My family was always big .30 cal. guys. - Less is really more , on hunt rifles lately, if shots are under 3-400 yds.

        My thoughts are - I may want a super lite wt. Grr bbl.

        A few of us are exploring new wts. for the bullets for Grendel whitetail hunting apps. Only half way thru the details, more to follow.

        The .308 does a fine job as a game getter in range, yet,, it's not as cool as the Grrr...

        Comment

        • bigbear_98
          Warrior
          • Aug 2013
          • 304

          #19
          I am amazed that learning how to true ballistic calculators has made such a huge difference for me. I surprise and impress myself and my shooting partners when we go to the range now, and its just a matter of having good data.

          LRRPF52 You answered a lot of questions posted in this thread in your post. Thanks.

          sneaky one, I have been very happy with the way my grendel performs. It surprises me. Sometimes I say to myself, "no way I just hit that".
          Last edited by bigbear_98; 09-16-2014, 02:49 AM.

          Comment

          • NugginFutz
            Chieftain
            • Aug 2013
            • 2622

            #20
            bigbear_98. It's not too late - join us in Utah, this week! LRRPF52 promises to open our eyes in several ways. 3 days, and counting...
            If it's true that we are here to help others, then what exactly are the others here for?

            Comment

            • bigbear_98
              Warrior
              • Aug 2013
              • 304

              #21
              After looking at the Lija 20" velocity thread, I think my krieger is right in line with the velocities everyone else is getting with 20" barrels and factory sst.

              Utah is a pretty big trek to just decide to go for the weekend. Y'all let me know what you learn. Post an aar.

              Comment

              • waveslayer
                Warrior
                • Jan 2013
                • 239

                #22
                Originally posted by bigbear_98 View Post
                After looking at the Lija 20" velocity thread, I think my krieger is right in line with the velocities everyone else is getting with 20" barrels and factory sst.

                Utah is a pretty big trek to just decide to go for the weekend. Y'all let me know what you learn. Post an aar.
                Quick Flight on AA and you will be in SLC, rent a cheap car and make the almost 2 hour drive south to Price. You will love it.

                Comment

                • bigbear_98
                  Warrior
                  • Aug 2013
                  • 304

                  #23
                  Soo.... I guess I have some crow to eat here.....

                  I took my rifles out and shot Friday at 250,500,750,and 1000. Both rifles were rocking steel at all distances, until I tried to shoot the Grendel at 1000. Now I went back to my data, compared the whiz wheel with my Ballistics app, both said 41.5 minutes of elevation, but I really needed 44 minutes.

                  Well, This bothered me. I switched back to my 308 and shot. I found things on the berm to shoot. Lazed them, looked at the chart, dialed the elevation, boom and hit. This was true data here. The 308 data was on. 250, 254, 500, 508, 745, 750, 755, 1000, 1008. Everything I aimed at I could hit with the 308. good numbers.

                  Ok go back to the Grendel and try to refine it as I did the 308. 250, 500 good... Wait was That a little low? Yes. So I ran everything all over again. I ran a box test on my scope. Good data there. tracks a little off at the high end but not bad and I can account for it. (Vortex PST)

                  So then I Shot at all distances I could. Took note of the elevation that It actually took to be zeroed at that distance, and compared to the numbers I already had. Well It was different. Close, but different.

                  I then set my chrono back up at 200 yards. Same number.

                  So I start to play with the BC of the bullet. I ran it down.... Way down.... And got the numbers on paper to match what I was really seeing. I kept the 200 yard velocity the same, lowered the BC, and raised the muzzle velocity.

                  Now I did all of this at a 3000 DA, so I am curious to see if it changes with the atmosphere, but It is exactly true right now. It is so true that, believe it or not, I couldn't miss with elevation. Wind was light, but enough to push 1-2 minutes, but elevation was perfect.

                  Comment

                  • bigbear_98
                    Warrior
                    • Aug 2013
                    • 304

                    #24
                    Edited to clean up the thread. The numbers are posted in post #44
                    Last edited by bigbear_98; 09-23-2014, 04:10 AM.

                    Comment

                    • cory
                      Chieftain
                      • Jun 2012
                      • 2985

                      #25
                      Originally posted by bigbear_98 View Post
                      Soo.... I guess I have some crow to eat here.....

                      I took my rifles out and shot Friday at 250,500,750,and 1000. Both rifles were rocking steel at all distances, until I tried to shoot the Grendel at 1000. Now I went back to my data, compared the whiz wheel with my Ballistics app, both said 41.5 minutes of elevation, but I really needed 44 minutes.

                      Well, This bothered me. I switched back to my 308 and shot. I found things on the berm to shoot. Lazed them, looked at the chart, dialed the elevation, boom and hit. This was true data here. The 308 data was on. 250, 254, 500, 508, 745, 750, 755, 1000, 1008. Everything I aimed at I could hit with the 308. good numbers.

                      Ok go back to the Grendel and try to refine it as I did the 308. 250, 500 good... Wait was That a little low? Yes. So I ran everything all over again. I ran a box test on my scope. Good data there. tracks a little off at the high end but not bad and I can account for it. (Vortex PST)

                      So then I Shot at all distances I could. Took note of the elevation that It actually took to be zeroed at that distance, and compared to the numbers I already had. Well It was different. Close, but different.

                      I then set my chrono back up at 200 yards. Same number.

                      So I start to play with the BC of the bullet. I ran it down.... Way down.... And got the numbers on paper to match what I was really seeing. I kept the 200 yard velocity the same, lowered the BC, and raised the muzzle velocity.

                      Now I did all of this at a 3000 DA, so I am curious to see if it changes with the atmosphere, but It is exactly true right now. It is so true that, believe it or not, I couldn't miss with elevation. Wind was light, but enough to push 1-2 minutes, but elevation was perfect.
                      I'm completely lost here. Eating crow on what exactly? What bullet (BC) were you using with what muzzle velocity? What did you have to change the BC and MV to?

                      The intent of this thread seems to be a passive aggressive shot at the Grendel.

                      If I'm wrong I apologize, If not man up and say what you want to say. I don't care for passive aggressive double talk.
                      "Those who sacrifice liberty for security, deserve neither." Benjamin Franklin

                      Comment

                      • bigbear_98
                        Warrior
                        • Aug 2013
                        • 304

                        #26
                        Edited to clean up the thread. The numbers are posted in post #44
                        Last edited by bigbear_98; 09-23-2014, 04:11 AM.

                        Comment

                        • bigbear_98
                          Warrior
                          • Aug 2013
                          • 304

                          #27
                          Originally posted by cory View Post
                          I'm completely lost here. Eating crow on what exactly? What bullet (BC) were you using with what muzzle velocity? What did you have to change the BC and MV to?

                          The intent of this thread seems to be a passive aggressive shot at the Grendel.

                          If I'm wrong I apologize, If not man up and say what you want to say. I don't care for passive aggressive double talk.
                          Not at all being passive aggressive. Never will I be. I try to say what I think. I am eating crow because in previous posts I stated that my data was right. When if fact it wasn't.

                          I love this rifle. I am just sharing my info. I can stop if it hurts feelings.

                          Comment

                          • BluntForceTrauma
                            Administrator
                            • Feb 2011
                            • 3897

                            #28
                            Let his data stand and we'll see what he's got. If nothing else, we can all learn something. Shooting at long range has a zillion micro variables.

                            For example, you can throw a football with a perfect spiral and it flies beautifully. But throw it badly and it wobbles like a duck. Same with bullets. If your barrel puts a beautiful spin on your bullet, it'll fly far and true. If your spin is less than perfect your bullet will wobble slightly and its frontal area will effectively increase, reducing the BC. Just an example of things that can account for performance differences between barrels.
                            :: 6.5 GRENDEL Deer and Targets :: 6mmARC Targets and Varmints and Deer :: 22 ARC Varmints and Targets

                            :: I Drank the Water :: Revelation 21:6 ::

                            Comment

                            • cory
                              Chieftain
                              • Jun 2012
                              • 2985

                              #29
                              Originally posted by bigbear_98 View Post
                              Not at all being passive aggressive. Never will I be. I try to say what I think. I am eating crow because in previous posts I stated that my data was right. When if fact it wasn't.

                              I love this rifle. I am just sharing my info. I can stop if it hurts feelings.
                              No need to worry about hurt feelings. It just came across as trying to demonstrate that the Grendel has no business being compared the .308, without outright saying it, in what has been an apples to oranges comparison.

                              Again I apologize if I'm wrong.

                              You're talking factory AMAX correct? There's a lot of Grendel guys with a lot of experience with this load. If your finding the BC to be off significantly, I'd look for a problem with your barrel, starting with your crown. What ballistic app are you using and what are your inputs? It may just be your ballistic app is off. What do you think your MV is and how confident are you in it?
                              "Those who sacrifice liberty for security, deserve neither." Benjamin Franklin

                              Comment

                              • bigbear_98
                                Warrior
                                • Aug 2013
                                • 304

                                #30
                                DON’T TAKE ANYTHING FOR GRANTED! The bottom line is to deal in absolute fundamentals, measure them, and remove all the assumptions. Don’t ever assume that something is what it says without measuring it. – Bryan Litz, Applied Ballistics for Long-Range Shooting


                                I took my information for granted. I had ordered a whiz wheel from Accuracy first after taking their class and getting what I thought was good data. I used the 123gr sierra match king as a reference to get my BC. It was what they told me to use, and it was pretty good. I have since refined what I see as good.

                                During this class I was having scope trouble. The scope at the time wasn't tracking true, I was uncomfortable behind the rifle, and the classroom provided Kestrel I was using kept crashing. I took the data that I had gathered from the class, thinking it was correct, and used it. It has been close up to 750 yards but not perfect. I jumped the gun so to speak by posting what I did in the beginning of this thread. I was only showing what I had thought was my real data.

                                I have shot a lot of rounds and hate being wrong. And when I'm wrong I like to fix the problem, find out what it was, and share my findings.

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