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

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  • Harpoon1
    Chieftain
    • Dec 2017
    • 1122

    #16
    So......made it out of there alive! No problems with the lockup, but several issues with the mags feeding and generally being under gassed.

    Ran 60 or 80 rounds of Wolf through it and one box each of Hornady 123 SST and ELD-M. Hated the Wolf, 4-5 MOA..bummer! Both the SST and ELD was around 1-1.5 MOA at 100. Not great but given the circumstances I can work with that. But the under gassing turned into a royal PITA. I grabbed the wrong lower, off a slammy carbine i hardly shoot anymore, and it was way over sprung for the midlength gas sytem and the Grendel. It had a red Sprinco spring and H3 buffer in it. Nada! Wouldn't lock open on the last round, wouldn't pick up another round. It went back just enough to reset the trigger and that was it. Finally figured that out and put another lower on there with a stock spring and buffer and it helped a little but there's still alot of room for improvement. The gas rings on the bolt were really snug in the carrier, so, I suppose things will improve somewhat as they wear in. I'm tempted to open up the gas port but may try a really light buffer spring and buffer first and see what happens.

    FWIW: some data points

    16" Ballistic Advantage barrel, in an Aero Precision upper, looks like maybe the Hanson profile barrel.

    Sea level, 40 F, clocked by Labradar

    Wolf 100 grn avg around 2460 fps, ES 81/23 SD
    SST 123 grn avg around 2325 fps, ES 58/ 14 SD
    ELD_M Black 123 grn avg 2345 fps, ES 39/11 SD
    Last edited by Harpoon1; 01-16-2018, 08:40 PM.

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    • koden
      Bloodstained
      • Sep 2014
      • 92

      #17
      Originally posted by Harpoon1 View Post
      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.
      Take the upper off the lower, remove the BCG. A loaded round or sized piece of brass should drop into the chamber with an audible thud with the barrel pointed straight down. If you point the barrel straight up the round or brass should drop out freely. I also take the ejector and extractor out of the bolt and place it in the chamber with a loaded round or sized brass. It should rotate freely when it gets past the bolt lugs but it should not be sloppy.

      Your prodding and pushing using the forward assist was probably just getting the bolt seated over the rim of the case (resistance caused by the ejector and extractor).

      Comment

      • bj139
        Chieftain
        • Mar 2017
        • 1968

        #18
        Break in needed with new parts.
        Lube it and shoot it and it will work better after a while.
        Accuracy is about what I and others here have experienced with rack grade barrels.
        Accuracy will be better with handloads.

        Comment

        • kcb38
          Warrior
          • Jun 2017
          • 220

          #19
          Originally posted by Harpoon1 View Post
          So......made it out of there alive! No problems with the lockup, but several issues with the mags feeding and generally being under gassed.
          Being under gassed seems to be a fairly common concern with BA barrels. They admittedly use smaller gas ports than other manufacturers. I'm hoping I don't have that issue with my new 20" rifle gas barrel. I couldn't measure the port precisely but it seems to be in the 0.08X range which might be a little on the small side. I guess time will tell. Oddly enough the only other BA barrel I have might be slightly over gassed, given the fact that the rifle ejects at about 2 o'clock.
          - Kirk -

          Comment

          • Harpoon1
            Chieftain
            • Dec 2017
            • 1122

            #20
            Originally posted by koden View Post
            Take the upper off the lower, remove the BCG. A loaded round or sized piece of brass should drop into the chamber with an audible thud with the barrel pointed straight down. If you point the barrel straight up the round or brass should drop out freely. I also take the ejector and extractor out of the bolt and place it in the chamber with a loaded round or sized brass. It should rotate freely when it gets past the bolt lugs but it should not be sloppy.

            Your prodding and pushing using the forward assist was probably just getting the bolt seated over the rim of the case (resistance caused by the ejector and extractor).
            Koden

            Good to know, I'll try that in the future.

            I snapped the empty brass under the extractor and then held it down against the ejector while feeding it into the chamber. It felt like the forward assit was to get the lugs to clear the barrel extension so it could go into lock up.

            Thanks for the help.

            Comment

            • Harpoon1
              Chieftain
              • Dec 2017
              • 1122

              #21
              Originally posted by bj139 View Post
              Break in needed with new parts.
              Lube it and shoot it and it will work better after a while.
              Accuracy is about what I and others here have experienced with rack grade barrels.
              Accuracy will be better with handloads.
              Agreed.

              I've thrown together 8 or 9 AR's now, and none have have the tight bolt clearances, going into lock up and/or in the bolt carrier itself that this gun has. I suppose that a good thing!

              Thanks

              Comment

              • Harpoon1
                Chieftain
                • Dec 2017
                • 1122

                #22
                Originally posted by kcb38 View Post
                Being under gassed seems to be a fairly common concern with BA barrels. They admittedly use smaller gas ports than other manufacturers. I'm hoping I don't have that issue with my new 20" rifle gas barrel. I couldn't measure the port precisely but it seems to be in the 0.08X range which might be a little on the small side. I guess time will tell. Oddly enough the only other BA barrel I have might be slightly over gassed, given the fact that the rifle ejects at about 2 o'clock.

                Kirk

                I drilled out the gas port on a 18", rifle length gas, FN barrel I got from PSA. Took two tries to get it big enough but it's still one of, if not the, most accurate AR's I own.

                Apples to Pineapples, I also have one of thier 16" 308 barrels in a M5E1 and it was perfectly gassed right out of the box.

                Thanks
                Last edited by Harpoon1; 01-17-2018, 10:05 PM.

                Comment

                • kcb38
                  Warrior
                  • Jun 2017
                  • 220

                  #23
                  Originally posted by Harpoon1 View Post
                  Kirk

                  I drilled out the gas port on a 18", rifle length gas, FN barrel I got from PSA. Took two tries to get it big enough but it's still one of, if not the, most accurate AR's I own.
                  Interesting. I have a 20" FN barrel from PSA as well but I haven't had a chance to really test its accuracy. Function wise it's been fine but I am looking forward to see how well it will group.
                  - Kirk -

                  Comment

                  • Harpoon1
                    Chieftain
                    • Dec 2017
                    • 1122

                    #24
                    Originally posted by kcb38 View Post
                    Interesting. I have a 20" FN barrel from PSA as well but I haven't had a chance to really test its accuracy. Function wise it's been fine but I am looking forward to see how well it will group.
                    Also have a new FN 15, with 20" barrel that looks greats and runs fine, eats everything. However, you couldn't hit the water with it, shooting it out of a boat! The bore looks prsitine, fantastic, and I can't find anything obviously wrong with it but the accuracy is pathetic. Im going to tear it down and give it a good going over sooner or later.

                    I've yet to get a 18" barrel with a rifle length gas system that I think is gassed properly. It's like they all use the same size gas port as a 20" barrel but, with only half the dwell time! Same thing today. Took another PSA 18" barrel, one of their "value" line, nitride in and out, and it's short stroking with Magtech 77 OTM. Getting ready to take the drill to it now.

                    Put another 150 rounds through the Grendel today as well. Mostly wolf, banging steel. Standard buffer and spring and it's breaking in nicely. Still had the occasional hiccup and bobble but, much better than the first day. Barrel apparently needs cleaning after only 250 rounds, SST's groups started to open up towards the end.
                    Last edited by Harpoon1; 01-19-2018, 08:40 PM.

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