Help with Hunting Build

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  • gnumadic
    Bloodstained
    • Dec 2017
    • 44

    Help with Hunting Build

    I recently picked up one of the 18" Faxon Group Buy barrels for my first 6.5 Grendel project. It is just my second AR build (the first being a 16" all-purpose rifle in .223 Wylde). My lower parts purchases are complete, but I have the majority of my upper parts to buy.

    Purpose: Hunting (primarily) and some long range shooting, both for me and my four kids (ages 8-16).

    Design Goals: Adjustable stock for multiple shooters. Light(er) weight for field carry. Two tone BLK/FDE. Scope only but option for BUIS a plus.

    Budget: $1200 before optics.

    Lower: I have spent $400 on the following.
    • Stag Arms Stripped Lower Receiver
    • CMMG PART KIT AR15 LOWER PINS/SPRING
    • BAD ENHANCED PIN SET
    • MAGPUL POLYMER TRIGGER GUARD BLK
    • RADIAN TALON SFTY SLCTR 2 LEVER BLK
    • BCM GUNFTR STOCK KIT MOD0 SOPMOD FDE
    • Strike Industries Enhanced Bolt Catch
    • Strike Industries Enhanced Magazine Catch - Black
    • LaRue Tactical A-PEG Grip FDE Smooth
    • LaRue Tactical MBT-2S Trigger


    Upper: The group buy barrel and a thread protector were $205 total, leaving $595 in the budget. I am decided on the upper parts except for the following...
    • Handguard - FDE in a 12"-13" length. Long enough to use a bipod, but not so long to add extra weight. Preference is a smooth top (no picatinny).
    • Gas Block - Adjustable...not to run suppressed but to reduce felt recoil and wear/tear, etc.


    My first AR build has a 13" ALG EMR V2 rail. While I like the EMR I've been leaning toward the Aero Precision ATLAS S-One, which is the same overall weight but with more aggressive cuts in the rail (it's the barrel nut that's a pig). But then I got the Faxon barrel and saw that the gas journal was clean (note: my first build has a Ballistic Advantage barrel that came with a pre-pinned low-profile gas block). I'm totally up for dimpling the barrel (more tools!), but in researching the process I stumbled across a multitude of opinions ranging from orthodox (anything less than pinning is heresy) to liberal (hey, if it's not a SHTF rifle then a clamp-on is just fine).

    Given the intended purpose for this build, I'd appreciate your thoughts/opinions/experiences on the following:
    1. Is an adjustable gas block worth it in the long run?
    2. Does a set-screw gas block (and/or pin) really affect accuracy?
    3. How much of a concern is handguard strike from a gas block when firing?


    The gas block I have been gravitating toward is the SLR Sentry 7. Their website says the set-screw model would fit the ATLAS S-One, but for the clamp-on model I'd need a handguard with an inner diameter of 1.35" or more. I'm now contemplating the SLR clamp-on gas block and maybe AP's Quantum handguard, which seems rock-solid and well priced (albeit a little fatter in the hand than I need/desire).
  • Frontier Gear
    Warrior
    • Nov 2017
    • 772

    #2
    Just my opinion, but hunting and long range shooting lead to different design decisions.

    For hunting I want light weight and Polymer (aluminum gets cold). Free float is not needed.

    Long range shooting makes me think of free float hand guards and heavy guns/barrels
    Engineer, FFL and Pastor

    Comment

    • gnumadic
      Bloodstained
      • Dec 2017
      • 44

      #3
      Originally posted by Frontier Gear View Post
      Just my opinion, but hunting and long range shooting lead to different design decisions.

      For hunting I want light weight and Polymer (aluminum gets cold). Free float is not needed.

      Long range shooting makes me think of free float hand guards and heavy guns/barrels
      Last edited by gnumadic; 02-19-2018, 04:12 AM.

      Comment

      • Frontier Gear
        Warrior
        • Nov 2017
        • 772

        #4
        Carbon fiber is good, just $$$. Magpul MOE-SLs work well.

        If you're hunting with factory ammo, I doubt that you would need an adjustable gas block. I is set screws on mine.
        Engineer, FFL and Pastor

        Comment

        • Lastrites
          Warrior
          • Apr 2017
          • 678

          #5
          Self stick stretch cloth camo tape works great for damping the cold, I've used the same roll over and over again for the past 5 years and it's due to be replaced. Just added thought out of my noodle if your concerned about aluminum free floats getting cold.

          Comment

          • gnumadic
            Bloodstained
            • Dec 2017
            • 44

            #6
            Originally posted by Frontier Gear View Post
            Carbon fiber is good, just $$$. Magpul MOE-SLs work well.

            If you're hunting with factory ammo, I doubt that you would need an adjustable gas block. I is set screws on mine.
            I hadn't considered the MOE-SL because I've always heard freefloat handguards were more accurate, particularly under bipod or sling usage. To your point I suppose for most hunting situations it wouldn't be that big of a difference. I'll put it on my list!

            In tracking sales/promos it seems I could still swing a 12" Brigand Arms Edge with my budget. Their Atlas model (w/front picatinny) or the Faxon Streamline carbon handguard would push it over just a little. I have a feeling that carbon fiber handguards are going to become more common and lower in price (with more options), much like what I've seen in the bicycle industry over the last decade.

            Originally posted by Lastrites View Post
            Self stick stretch cloth camo tape works great for damping the cold, I've used the same roll over and over again for the past 5 years and it's due to be replaced. Just added thought out of my noodle if your concerned about aluminum free floats getting cold.
            That's a great idea. And I'd only need it during cold weather!

            Comment

            • rabiddawg
              Chieftain
              • Feb 2013
              • 1664

              #7
              If it’s cold I put my hands in my pockets. I don’t hold my gun to warm my hands
              Knowing everthing isnt as important as knowing where to find it.

              Mark Twain

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

              Comment

              • gnumadic
                Bloodstained
                • Dec 2017
                • 44

                #8
                Originally posted by rabiddawg View Post
                If it’s cold I put my hands in my pockets. I don’t hold my gun to warm my hands
                Haha! I know what you mean. Maybe I could wrap the handguard with tape and hand warmers!

                Comment

                • dpete
                  Warrior
                  • May 2016
                  • 222

                  #9
                  Originally posted by gnumadic View Post
                  Haha! I know what you mean. Maybe I could wrap the handguard with tape and hand warmers!
                  I'm thinking of using 3M vetwrap next season to wrap my aluminum handguards with in below freezing temps. It comes in multiple colors and it is what the "sticks to itself" camo wraps are based on. Using a roll of black and white and staggering the wraps you could even come up with a snow camo pattern, or tan and black for fall leaves.

                  Comment

                  • Crusty
                    Warrior
                    • Dec 2017
                    • 237

                    #10
                    I became a free float believer after seeing a guy clamp down a barrelled upper receiver to the table on his milling machine, putting a 3lb sideways pull on the barrel and then measuring the muzzle deflection from the pull. The deflection amounted to a 5/8" change in POI at 100 yards. Since I routinely put more than 3lbs of tension on a sling when I'm shooting I recognize the elimination of inaccuracy that a free float handguard provides.

                    When it's cold I often wear gloves and since I dislike oil can sized hand guards I don't find gloves to be any particular nuisance.
                    I'll be yer Huckleberry.

                    Comment

                    • gnumadic
                      Bloodstained
                      • Dec 2017
                      • 44

                      #11
                      Thanks for all of the input. If I go back to my original questions...
                      1. Is an adjustable gas block worth it in the long run?
                      2. Does a set-screw gas block (and/or pin) really affect accuracy?
                      3. How much of a concern is handguard strike from a gas block when firing?

                      ...then I think what I'm hearing is that I don't need an adjustable gas block if I'm going to be shooting factory loads (at least not anytime soon). Also, while I do care about accuracy this is not a precision 800-1000 yard rig. So a set-screw gas block is fine for my needs. Lastly, while aluminum conducts cold there are other less expensive methods to help mitigate any discomfort.

                      Compared to the SLR gas block and a carbon fiber handguard, I could save $200 or more if I go with a simple low-profile gas block and an aluminum handguard. That's good money toward a mount and optic.

                      Comment

                      • Crusty
                        Warrior
                        • Dec 2017
                        • 237

                        #12
                        Having both kinds, I think a fixed gas block is better than an adjustable one because it doesn't have to be taken apart periodically and cleaned or parts replaced after it gets fire worn. If a barrel's port is too large I've started making fixed SST restrictors that install inside a standard gas block between the barrel and the gas tube. It also means less weight out towards the muzzle which makes the rifle a tiny bit easier to maneuver in fast shot situations that you can encounter when hunting. I try to keep my hunting rifles light and especially so out towards the flashy end.

                        In answer to one of your questions, a free floating barrel not touching anything has the least potential to be affected by things which disturb its normal vibration and accuracy, so a gas block knocking against something isn't as good.
                        Last edited by Crusty; 02-20-2018, 06:42 PM.
                        I'll be yer Huckleberry.

                        Comment

                        • LRRPF52
                          Super Moderator
                          • Sep 2014
                          • 8569

                          #13
                          1. Is an adjustable gas block worth it in the long run?
                          2. Does a set-screw gas block (and/or pin) really affect accuracy?
                          3. How much of a concern is handguard strike from a gas block when firing?
                          1. Adjustable gas is sometimes necessary for 18" MLGS if the gas port is cut too large. It can help increase parts life by reducing torsion on the bolt and extractor. I haven't used one on any of my 18" MLGS builds so far, but I do have a Bootleg carrier with adj gas.

                          2. With the gas block, you first want to be concerned more with reliability. When the gas block slip-fits over the journal, there is a lot of gas leakage that robs the Stoner Internal Expansion System of the required energy to pressure-up the back of the bolt and the inside of the carrier to generate ideal carrier inertia. We want that gas block properly aligned with gas port in the barrel, and we want the mating surfaces so tight with each other, there is no room for gas to escape. This is the biggest single aspect of AR15 builds that people overlook, and then have all sorts of problems with cycling because their window of operation is so narrow now.

                          The gas tube is also supposed to press-fit into the gas block so that there is no leakage, but this would then knock out 99% of the home-builders from being able to assemble their lego sets. Parts market solution". Cut the holes so that the tube slips easily in. This is why I bed my gas tubes as well.

                          As far as accuracy goes, Bill Alexander related that out of a fleet sample of early GDMR rifles he produced, half of them shot right out of the gate without any gas block bedding, and the other half would not, all parts and assembly methods being the same. He then looked at bedding the blocks and tubes, which tightened them up with the other rifles.

                          For those who have some of the early GDMRs and figured they needed to be modified with a different handguard, they quickly saw that it required a heat gun to get any of the gas block parts off. The tubes were pretty much permanently fixed to the blocks. I have one in my shop that someone pulled and gave to me.

                          3. Gas block interference with handguard ID is incidental to a really lightweight profile barrel with a clamp-on or larger gas block inside a tight ID handguard. Use a low profile gas block with enough clearance if you are going to source a whippy barrel.
                          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

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