No HeadSpace Gauges, Whats The Likelyhood I'll Blow MY Face Off?

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  • Harpoon1
    Chieftain
    • Dec 2017
    • 1122

    No HeadSpace Gauges, Whats The Likelyhood I'll Blow MY Face Off?

    Just recieved an Aero Precision complete upper, from the factory. Also have a brand new AA bolt to go along with it and was planning on using that in a BCM bolt carrier.

    So, ............short of waiting on headspace gauges, are there any other things I could check/do, to increase my odds of not having any problems.

    Or, have I've completely lost my mind if i think Im going to shoot this thing before checking the headspace?
    Last edited by Harpoon1; 01-12-2018, 11:33 PM.
  • grayfox
    Chieftain
    • Jan 2017
    • 4295

    #2
    As long as they are both spec'd to the same dimensional bolt face depth, and as long as you have mocked them up with an empty unfired brass casing....
    I do an upper/complete bcg/bolt/charger/empty casing check (ie, no lowers, no loaded ammo) on the ones I plan to use together to ensure proper fit. Guide the casing in with your fingers after seating it against the ejector and engaged with the extractor.

    I haven't been in the mode of verifying every head space setting on barrels I received from reputable vendors...
    I do verify that both are for 0.136 bolt face depths (I don't care for the 0.125 version although they may work just fine, I have no experience with them).
    The barrel/extension and the bolt face both need to be for either 0.136" bolt face depth or 0.125". IIRC Aero should be 0.136 and should say something in its specs like "Grendel 0.136" or "Grendel II" head spacing.
    You can measure your bolt face depth with a caliper.
    "Down the floor, out the door, Go Brandon Go!!!!!"

    Comment

    • grayfox
      Chieftain
      • Jan 2017
      • 4295

      #3
      O yeah one more thing... sometimes guys have found that even one type of factory ammo (pick your flavor) may not totally seat into their new chambers... so after all of that, it may be wise to verify that your ammo will seat properly... I have not encountered that problem but there are a few posts on the forum that talk about it.
      "Down the floor, out the door, Go Brandon Go!!!!!"

      Comment

      • Harpoon1
        Chieftain
        • Dec 2017
        • 1122

        #4
        Yep, Aero Precision uses Ballistic Advatage barrels and they advertise "type II " chambers. The AA bolt is supposed to be 0.136 but I'll verify that and make doubly sure.

        The rest sounds good, thanks.
        Last edited by Harpoon1; 01-12-2018, 11:40 PM.

        Comment

        • Drillboss
          Warrior
          • Jan 2015
          • 894

          #5
          I would put it together and fire the first round, single loaded, from the hip (with eye protection, hearing protection, etc). Confirm that it locks back on the empty mag.

          Do you happen to have the Hornady Headspace guage comparators? If so, compare your fired case dimensions to SAAMI specs.

          After building 3 or 4 Grendel uppers, I finally bought the Manson headspace gages. Measuring the gages indicated that if the fired case measures within the SAAMI specs, then you are good to go. I can go back to my my notes and provide more details if needed.

          Comment

          • Harpoon1
            Chieftain
            • Dec 2017
            • 1122

            #6
            Drillboss,

            Sounds like a good plan.

            Unfortunately, I've got nothing other than a micrometer at this point. I'll run a few rounds through it and see how everything looks. Im sure I'll have plenty of help and advice tomorrow at the range.

            Thanks for your help.

            Comment

            • Drillboss
              Warrior
              • Jan 2015
              • 894

              #7
              Headspace too tight: Round won't chamber.
              Headspace too loose: Potential for a parted case.

              If your barrel's chamber was machined for the proper bolt face depth, then manufacturing tolerances should put the headspace within where it needs to be. This is just my opinion based on what I've seen with my barrels. If anyone has other experiences, please chime in.

              Comment

              • VASCAR2
                Chieftain
                • Mar 2011
                • 6218

                #8
                I know it's not Grendel related but does anybody have a set of 22-250 gauges they'd like to sell or rent to me. This is a one time usage project, doing a barrel swap on a Savage.

                Comment

                • Harpoon1
                  Chieftain
                  • Dec 2017
                  • 1122

                  #9
                  Originally posted by VASCAR2 View Post
                  Take a look at this thread, has information on where to rent gauges and other solutions.

                  This thread didn’t specifically apply to the 6.5 Grendel but still is relevant to this thread.


                  http://www.65grendel.com/forum/showt...adspace-Gauges

                  Thanks VASCAR2

                  Comment

                  • Klem
                    Chieftain
                    • Aug 2013
                    • 3507

                    #10
                    If you always fire the first round of a new barrel from the hip, and look away as you pull the trigger the likelihood your face will be injured is...zero.

                    Comment

                    • Sticks
                      Chieftain
                      • Dec 2016
                      • 1922

                      #11
                      Originally posted by Klem View Post
                      If you always fire the first round of a new barrel from the hip, and look away as you pull the trigger the likelihood your face will be injured is...zero.
                      Your lower regions however...

                      Headspace gauges and reamer rent for Grendel

                      Sticks

                      Catchy sig line here.

                      Comment

                      • sschefer
                        Bloodstained
                        • Jan 2018
                        • 26

                        #12
                        Originally posted by Drillboss View Post
                        Headspace too tight: Round won't chamber.
                        Headspace too loose: Potential for a parted case.

                        If your barrel's chamber was machined for the proper bolt face depth, then manufacturing tolerances should put the headspace within where it needs to be. This is just my opinion based on what I've seen with my barrels. If anyone has other experiences, please chime in.
                        From my experience, this is 100% correct. Headspace is set to standards that will allow for re-use of brass/re-loaded ammo. If you look at what the military uses you'll find that a bolt is allowed to have more head space than what we call max because the military never uses re-loads and the risk of a parted case is far less likely. Will a parted case blow up in your face.. Not likely, the bolt will still be in locked in place. Will it be a pain in the arse to remove the parted case.. Yeah, but they make tools that make it pretty easy.

                        Comment

                        • Harpoon1
                          Chieftain
                          • Dec 2017
                          • 1122

                          #13
                          Klem & Sticks

                          Pulled a bullet and tried some new Hornady brass. Definitely on the "snug" side going in. Needed a little prodding, some forward assit, to send it all the way home. Thats good, I think? Better than too loose "ey" ? And, the bolt lugs are tight, not much clearance coming out of lock up. Not sure what to make of that though. Difinitely much tighter than any other AR I've put together.

                          Anyway, Im going to be cautious firing the first round or two, probably shoot it from around the corner, and from behind a barricade of some sort!

                          Thanks

                          Comment

                          • Klem
                            Chieftain
                            • Aug 2013
                            • 3507

                            #14
                            Originally posted by Sticks View Post
                            Well...what can I say? If you're worried about any part of your body getting injured you could knock-up a 'drip rifle'. The delay firing mechanism saved quite a few lives during the Gallipoli withdrawal in WW1.


                            On a more serious note you could dig a section of 100mm PVC pipe into a earth mound like a safety-clear tube. Seems like a lot of effort for the risk though.

                            Comment

                            • bj139
                              Chieftain
                              • Mar 2017
                              • 1968

                              #15
                              Firing my Grendel WITHOUT a gas block, gas tube, buffer or buffer spring.
                              It worked fine.
                              It had to be slammed closed since there was no spring assist but the manual extraction was easier since there was no spring desist.
                              IMG_20170802_132336 (Medium).jpg

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