Barrel spec advice

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  • DontWorryScro
    Unwashed
    • Jan 2018
    • 20

    Barrel spec advice

    I'm in the process of building a 6.5 Grendel on the AR platform. I'd like to mostly use it as a longer range (>600) precision shooter for punching paper but not be so bench-centric as to forgo any kind of mobility should I embark on a rare hunting trip. This is why I think I'd like to avoid full on bull barrel and other ultra heavy options meant for bench-only guns.

    I've got a friend I consider to be very well versed in the world of firearms. I defer to him on all things AR building but just wanted to run these specs by a community who specializes in 6.5 Grendel.

    What I have so far is:

    Lower:
    • Aero Precision STS lower receiver
    • CMMG LPK w/ V Seven Hybrid Ambi 57degree safety
    • La Rue MBT 2 stage trigger
    • Luth AR rifle length fixed stock kit with buffer tube, buffr spring, weight + stock
    • Magpul MIAD grip


    Upper:
    • Aero Precision no FA Slick Side upper receiver w/ port door
    • Aero Precision SS rifle length gas tube
    • Toolcraft Nitride 6.5G Type II BCG
    • Superlative Arms .750 clamp-on adjustable gas block
    • SJC Titan .30 cal comp (but considering going the thread protector route for starters and attaching the muzzle device if needed later)


    So what I need still is the handguard, the barrel and probably some Strike Industries Extended charging handle.

    I'm considering going all the way with a Craddock Bartlein barrel and the specs I was given to have one spun up for me are as follows:
    • 20"-24"
    • Anything from medium to semi-bull
    • 1in or 1.2in to a gas port that is .750 and then steps down just a bit if at all to the muzzle
    • .30cal (5/8x24) threads.

    Not sure about twist.

    I'm also all ears on your favorite handguards. I've been looking at ALG EMR, Aero Quantum and Midwest Industries. Maybe a Seekins?
    Last edited by DontWorryScro; 02-19-2018, 01:16 AM. Reason: threading clarification
  • grayfox
    Chieftain
    • Jan 2017
    • 4295

    #2
    Welcome DWS! Grendels are great rifles.
    Lots of these parts are personal preference and/or there are several good-to-excellent pieces, I don't call myself qualified enough to comment on a lot of them.
    Here are my $0.02 for you to consider however:

    1. You can certainly get to 600 and, I think, further with 20", any longer and your occasional hunt will be packin' a lot of rifle IMO. I'd personally stick to 20 unless you are bench-rest pro, (those guys are above my paygrade)! Getting into >22" I think might call for a gas system longer than RLGS, your fab shop would know. Grendels don't lose MV/drop as much as many other calibers do so you don't need a mile-long barrel.
    2. The "30 cal" threads is not specific enough. Recommend 5/8x24 threads, that's what fits most devices and is the US norm for "30 cal", although there are others I've read about.
    3. My barrels haven't gone over, what, maybe 0.800 down to 0.700-0.720 and are plenty hefty for longer ranges, again IMO. Getting into the 1"+ diameters again means more weight, if you want it, go for it. (one or two of them are about a "Size 6" and they are in this diameter range).
    4. 0.750 gas port is fairly standard. You might think about an adjustable gas block, but for RLGS a fixed GB should be gentle enough.
    5. I've been very happy with the Midwest Industried handguards. I do have one that is a Troy alpha battle rail (Mlok), lite-weight, that is real nice also. Go for a quality one with laser-etched T-marks, some of the budget HGs don't have them and I prefer them to be there.

    6. 1:8 twist is the norm, certainly not slower than. Some do 1:7.5ish but I have no experience there.

    Do your break in carefully, use factory ammo, no steel case (again, IMO). Make sure the upper face is square for the barrel, some guys lap it to be certain.

    I should stop here only to add there are a bunch of much more knowledgeable guys on here and they will probably chime in, but this might give you some things to consider.

    We just started a new print run of Volume I (4th Printing) and Volume II (2nd Printing). No changes were made to Volume I from the 3rd Printing, which includes the updated Western Powders data from 2014. Some slight changes were made to Volume II. We fixed a small typo on page 48 referring to figure 6.7 when it should


    Get these Grendel handbooks, they are worth gold to you!
    "Down the floor, out the door, Go Brandon Go!!!!!"

    Comment

    • DontWorryScro
      Unwashed
      • Jan 2018
      • 20

      #3
      Originally posted by grayfox View Post
      Welcome DWS! Grendels are great rifles.
      Lots of these parts are personal preference and/or there are several good-to-excellent pieces, I don't call myself qualified enough to comment on a lot of them.
      Here are my $0.02 for you to consider however:

      1. You can certainly get to 600 and, I think, further with 20", any longer and your occasional hunt will be packin' a lot of rifle IMO. I'd personally stick to 20 unless you are bench-rest pro, (those guys are above my paygrade)! Getting into >22" I think might call for a gas system longer than RLGS, your fab shop would know. Grendels don't lose MV/drop as much as many other calibers do so you don't need a mile-long barrel.
      2. The "30 cal" threads is not specific enough. Recommend 5/8x24 threads, that's what fits most devices and is the US norm for "30 cal", although there are others I've read about.
      3. My barrels haven't gone over, what, maybe 0.800 down to 0.700-0.720 and are plenty hefty for longer ranges, again IMO. Getting into the 1"+ diameters again means more weight, if you want it, go for it. (one or two of them are about a "Size 6" and they are in this diameter range).
      4. 0.750 gas port is fairly standard. You might think about an adjustable gas block, but for RLGS a fixed GB should be gentle enough.
      5. I've been very happy with the Midwest Industried handguards. I do have one that is a Troy alpha battle rail (Mlok), lite-weight, that is real nice also. Go for a quality one with laser-etched T-marks, some of the budget HGs don't have them and I prefer them to be there.

      6. 1:8 twist is the norm, certainly not slower than. Some do 1:7.5ish but I have no experience there.

      Do your break in carefully, use factory ammo, no steel case (again, IMO). Make sure the upper face is square for the barrel, some guys lap it to be certain.

      I should stop here only to add there are a bunch of much more knowledgeable guys on here and they will probably chime in, but this might give you some things to consider.

      We just started a new print run of Volume I (4th Printing) and Volume II (2nd Printing). No changes were made to Volume I from the 3rd Printing, which includes the updated Western Powders data from 2014. Some slight changes were made to Volume II. We fixed a small typo on page 48 referring to figure 6.7 when it should


      Get these Grendel handbooks, they are worth gold to you!
      Thanks for the kind welcome, grayfox!

      Precisely the kind of response I was seeking so I appreciate it!

      1. I am certainly leaning towards 20" so your assessment reinforces my inclination.
      2. Good point, yes to clarify I am referring to 5/8x24 threads
      3/4. I'm aiming for .750 mostly because I already have a Superlative Arms .750 clamp on adjustable gas block sitting in my toolbox
      5. I've seen those Troy HG's and I actually do really like their design. I should probably get honest with myself and include those in my list of handguard options. Something about those circles... :P

      Do you have magazine preferences? I have a E-Lander 10 round I bought early on to ensure my lower build was in good working order.
      I also have a small box of Hornady 123 grain ELD match "Black" to test out once the build is complete.

      I'll say once I dial in the specs for the barrel I plan to send in my Toolcraft bolt to get headspaced to the barrel. Frankly I'll probably send all my upper parts to Craddock when I order the barrel and have them just build the upper for me as I don't have the tools or workspace to do it on my own.

      Comment

      • StoneHendge
        Chieftain
        • May 2016
        • 2009

        #4
        I'm a huge fan of the ALG barrel nut / barrel Interface. Takes a little longer to get it together, especially the first go round, but you know your going to be torqued right, don't have any worries about the gas tube touching the barrel nut, and it's as secure as it can get with the screws that hold it into the barrel nut not impacting the barrel whatsoever. If I'm building something where accuracy is paramount, I can't think of anything else I'd use other than an Enhanced Aero upper receiver and handguard, and I've been super impressed by everything that Bill Geissele has sold me. They are slim, so I would doublecheck your block would fit under one. Superlative and ALG do have dimension drawings on their websites.

        I do have an Aero Quantum on my 458 Socom. The finish reflects the price point and they are wide. As in big. Does fine for my application, but I doubt it's too fun to hold offhand. I put a FAB pistol foregrip with a 700 lumen flashlight on my Socom so that aspect is moot to me (and if anyone is ever in need of having a dark tunnel cleared, you know who to call).

        I also have a Troy Battle Rail on my 300 BLK carbine. Love the weight and feel. I really don't like that the 3 screws that hold it on go directly against the barrel. Fine for my carbine with a 1x 3 moa red dot, but don't do that to a Bartlein!
        Last edited by StoneHendge; 02-19-2018, 03:17 AM.
        Let's go Brandon!

        Comment

        • ricsmall
          Warrior
          • Sep 2014
          • 987

          #5
          For the purpose stated, I would go with a medium heavy contour. Normal chamber area 1”-1.2, step down to .850 to GB journal, .875 GB, then step back to .850. I like 22”’ for a dual purpose bench/Hunting gun. This is the setup I run and it works for me. Also would go with an ACS stock and 5.2 oz carbine buffer on RLG system.
          Member since 2011, data lost in last hack attack

          Comment

          • Bigs28
            Chieftain
            • Feb 2016
            • 1786

            #6
            I love these handguards. Expensive but will save you a half poundish most likely.

            The handguard is the most visible and most handled part of a rifle: the one you choose will define the style, weight, ergonomics, and performance of your AR-10 or AR-15 firearm. Ultra-lightweight is only the starting point for what our NOAX handguards offer. Aerospace carbon fiber make this guard stronger than aluminum at below half the weight. The lattice structure provides a solid and repeatable grip and allows versatile accessory mounting at almost any angle. It insulates your forehand and provides airflow ensures superior barrel cooling rates for accuracy even in sustained fire.  For precision shooting, our free-floating barrel nut puts no pressure on the barrel and will never change your point of impact. We know that’s a lot to promise, that’s why we back these claims with our industry leading warranty. We offer the NOAX handguard in lengths from 7” to 15” to match your shooting style and rifle setup. The carbon lattice material is complemented by our deep-black hard-anodized aluminum end-caps which allow easy mounting to your upper receiver and protect the leading edge from impact.
            Last edited by Bigs28; 02-19-2018, 02:18 PM.

            Comment

            • mdram
              Warrior
              • Sep 2016
              • 941

              #7
              talk with craddock a bit. when i emailed them last year they were using .264 lbc chamber
              this is the email i was sent

              "We had been making our own blanks but due to the time it takes I've been using Green Mountain as a substitute, they shoot just fine and I hold either on par with Shilen or Douglas. We've been using the .264 LBC chamber for the past year and it's completely fixed the problems we had been having using the Grendel reamer (pressure issues and accuracy limitations). If you want to send a bolt we'll headspace to it, I don't stock them but prefer JP on the Grendel builds."
              just some targets for printing
              https://drive.google.com/drive/folde...xQ?usp=sharing

              Comment

              • grayfox
                Chieftain
                • Jan 2017
                • 4295

                #8
                That's a caution flag to me.
                I've had 2 LBC match barrels and now 3 SAAMI's; there's nothing wrong in the SAAMI Grendel spec that an LBC needs to fix. I sold the LBC's.
                LBC style has its proponents and that's fine, -- I'm just sayin' for me I'm not going there, of course everyone has their own choice to make on it.

                Any problems Craddock may have had are probably traceable to other mfg issues or reamer-specific issues, no offense but I personally don't buy that reasoning any more as a justification to go away from the original on this cartridge. Maybe they're right, I don't know, but as a buyer I'm not convinced any more on "pressure and accuracy" nits that the LBC is supposed to correct.

                If you want Bartlein or Krieger or Lilja (the premium barrels) don't let someone talk you into another make.
                "Down the floor, out the door, Go Brandon Go!!!!!"

                Comment

                • ricsmall
                  Warrior
                  • Sep 2014
                  • 987

                  #9
                  Originally posted by grayfox View Post
                  That's a caution flag to me.
                  I've had 2 LBC match barrels and now 3 SAAMI's; there's nothing wrong in the SAAMI Grendel spec that an LBC needs to fix. I sold the LBC's.
                  LBC style has its proponents and that's fine, -- I'm just sayin' for me I'm not going there, of course everyone has their own choice to make on it.

                  Any problems Craddock may have had are probably traceable to other mfg issues or reamer-specific issues, no offense but I personally don't buy that reasoning any more as a justification to go away from the original on this cartridge. Maybe they're right, I don't know, but as a buyer I'm not convinced any more on "pressure and accuracy" nits that the LBC is supposed to correct.

                  If you want Bartlein or Krieger or Lilja (the premium barrels) don't let someone talk you into another make.
                  Ill second everything in this post. If the saami reamer has the correct freebore ground and not to minimum spec, it is good to go.
                  Member since 2011, data lost in last hack attack

                  Comment

                  • DontWorryScro
                    Unwashed
                    • Jan 2018
                    • 20

                    #10
                    Really appreciating these insights. For my input when I contacted Craddock a month or so ago just doing some prelim fact finding and sussing out potential future builds they gave no indication that they would steer me away from Bartlein or any spec I was after. Straight up said they could absolutely do it. I'll probably reach out again with more precise specs and confirm once I lock down the exact barrel I want made.

                    Here's another question. I have a 13.5" V Seven 2099 Enlightened handguard that I've been trying to sell at a loss. I'd only mounted it on my 5.56 HD/SHTF newly built, never fired rifle for a few days before I realized I wanted to go longer to 15" for aesthetic reasons on the 14.5" barrel with an SLR linear comp. In any case, I've been trying to sell it unsuccessfully and when I do I'm going to take like a 30% hit on it at least. Is there any reason why I shouldn't just keep it and use it on a Grendel build sitting around a 20" barrel? Would the gas block be exposed at the end of a rifle length gas tube?

                    Comment

                    • Bigs28
                      Chieftain
                      • Feb 2016
                      • 1786

                      #11
                      Try precision firearms. They will make you a grendel bartlein barrel.

                      Comment

                      • grayfox
                        Chieftain
                        • Jan 2017
                        • 4295

                        #12
                        Originally posted by Bigs28 View Post
                        Try precision firearms. They will make you a grendel bartlein barrel.
                        +1 from here.....
                        "Down the floor, out the door, Go Brandon Go!!!!!"

                        Comment

                        • Drillboss
                          Warrior
                          • Jan 2015
                          • 894

                          #13
                          Originally posted by DontWorryScro View Post
                          Really appreciating these insights. For my input when I contacted Craddock a month or so ago just doing some prelim fact finding and sussing out potential future builds they gave no indication that they would steer me away from Bartlein or any spec I was after. Straight up said they could absolutely do it. I'll probably reach out again with more precise specs and confirm once I lock down the exact barrel I want made.

                          Here's another question. I have a 13.5" V Seven 2099 Enlightened handguard that I've been trying to sell at a loss. I'd only mounted it on my 5.56 HD/SHTF newly built, never fired rifle for a few days before I realized I wanted to go longer to 15" for aesthetic reasons on the 14.5" barrel with an SLR linear comp. In any case, I've been trying to sell it unsuccessfully and when I do I'm going to take like a 30% hit on it at least. Is there any reason why I shouldn't just keep it and use it on a Grendel build sitting around a 20" barrel? Would the gas block be exposed at the end of a rifle length gas tube?
                          Looks like it will be exposed a little bit. I just measured mine and it's 13-5/8" from the front of the gas block to the back of the handguard.

                          Put it on and see what you think.

                          Comment

                          • DontWorryScro
                            Unwashed
                            • Jan 2018
                            • 20

                            #14
                            Originally posted by Drillboss View Post
                            Looks like it will be exposed a little bit. I just measured mine and it's 13-5/8" from the front of the gas block to the back of the handguard.

                            Put it on and see what you think.
                            Ya I just saw some pics online and it looks it will protrude just a bit as you have said. I'll opt for a 15" and keep trying to sell my 13.5" V7 Enlightened handguard. Thanks for measuring!

                            Comment

                            • Drillboss
                              Warrior
                              • Jan 2015
                              • 894

                              #15
                              Originally posted by DontWorryScro View Post
                              Ya I just saw some pics online and it looks it will protrude just a bit as you have said. I'll opt for a 15" and keep trying to sell my 13.5" V7 Enlightened handguard. Thanks for measuring!
                              I'm somewhat in recovery from this Black Rifle Addiction and I've got a 12" on that rifle, rather than having already bought another 15".

                              Comment

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