What Buffer?

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  • blofeld42
    Unwashed
    • Sep 2012
    • 13

    What Buffer?

    Got a 16" AA upper and a lower with a Magpul STR telestock. In all likelihood it's got a carbine buffer weight in there.

    It worked great with Wolf steel case 100gr. I got a couple failures to go into battery today with Wolf Gold 120 gr, looked like it was almost a bolt override.

    Would a heavier buffer help?
  • LRRPF52
    Super Moderator
    • Sep 2014
    • 8569

    #2
    Describe the malfunctions in more detail, or provide pics if possible.

    Is the upper a complete AA 16" upper group?

    What type of gas block do you have, and is it installed with the ports aligned?

    Is your ejector radiused?

    Type of bolt carrier? AR15, M16? Well lubed?
    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

    • blofeld42
      Unwashed
      • Sep 2012
      • 13

      #3
      AA Arms 16" Incursion upper, complete. Magpul STR stock & buffer. It will be at least a couple weeks before I can get to the range again.

      About 45 rounds fired. Twice it seemed that the bolt didn't quite go into battery. The trigger tripped, but there was no primer strike on one and a very light primer strike on the other. (I didn't try to use the FA to put it into battery, so I'm not sure it was the case that it was out of battery.) One of the cases was scratched, as if it was being chambered with too much of a nose-up angle. In the third case it was a failure to feed--cartridge nose-up, bolt head caught only the upper rim of the cartridge.

      This was with Wolf Gold 120gr. The steel case 100gr worked fine, consistent ejection pattern at about 4:00-4:30.

      Comment

      • sneaky one
        Chieftain
        • Mar 2011
        • 3077

        #4
        Try some other ammo- wolfie is hit or miss., mostly a 50 % miss. As far as buffers- try an H2, H1
        Last edited by sneaky one; 05-02-2015, 03:30 AM.

        Comment

        • LRRPF52
          Super Moderator
          • Sep 2014
          • 8569

          #5
          Lubrication and spring strength might help also. For the 16" MLGS AA set-up, I use an H2 buffer and have not had failure to go into battery malfs since I got the barrel bolt combo and threw it in an upper way back. Haven't had any malfs really, except when I tried to use a 5.56 PMAG just out of curiosity.

          There are some little tweaks you can do to enhance reliability with the PPC-based AR15's, namely radiusing the ejector, blending and polishing the feed ramps carefully, and balancing the gas and recoil systems. Check the mags to have correct angles on the feed lips. Pretty easy stuff.
          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

          • blofeld42
            Unwashed
            • Sep 2012
            • 13

            #6
            Failure to Feed

            Finally got out again. With pics this time.

            Changed the buffer to H2, no real effect. It's ejecting at about 4:30-5:00. As mentioned the 100 gr Wolf steel case works fine, 120 gr Wolf Gold does not.

            Sometimes jarring the rifle a bit will cause it to go the rest of the way into battery. There's a definite ding on the case where the cartridge is not aligned, and a bit of a gouge on the rim case where the extractor hit.

            What's this radiusing the ejector all about?
            Attached Files

            Comment

            • LRRPF52
              Super Moderator
              • Sep 2014
              • 8569

              #7
              I don't know what's causing your FTFeed going into battery stoppage, but you could radius the ejector. How much lubrication are you putting on the bolt carrier rails? They should be wet with thick lube, preferably.


              Radiused ejector
              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

              • Klem
                Chieftain
                • Aug 2013
                • 3507

                #8
                Interesting...

                Another possibility;
                If a new gun it could be the bolt is not lapped to the teeth of the barrel extension. It could simply be a case of working it in by hand (sit it in your lap and pull it out of battery an inch and let it go a hundred times while watching telly). Or, if the barrel extension lugs are not perfectly lined up then there will be too much friction as the new bolt goes in unless it has plenty of momentum.

                I read Wolf 100 is lacquered steel cases from Russia whereas Wolf 120 is brass made by Privi Partizan in Serbia. Is this right? You guys would know. If so then slightly different ammo dimensions and pressures suggest it is on the edge of working, so not catastrophic.

                Ejecting at 5pm usually means it is at the lower end of cycling energy. A heavier buffer will not help in this situation.

                Does it lock back properly on the last round? On the face of the bolt and not the carrier?

                Comment

                • blofeld42
                  Unwashed
                  • Sep 2012
                  • 13

                  #9
                  I usually have the rails somewhat dry, but I'd prefer that it work with enough margin even if not well lubed, and it's failing somewhat consistently. This cropped up after about 60 rounds.

                  What does radiusing the ejector do?

                  Comment

                  • blofeld42
                    Unwashed
                    • Sep 2012
                    • 13

                    #10
                    It's never failed to lock back on last round.

                    Yep, the steel case is Russian, and Wolf Gold is Serbian. I suppose I could try some other brass 120-ish gr ammo and see what happens. The Wolf Gold definitely has a longer COAL, which may be affecting it.

                    Comment

                    • Variable
                      Chieftain
                      • Mar 2011
                      • 2403

                      #11
                      Originally posted by Klem View Post
                      Interesting...

                      Another possibility;
                      If a new gun it could be the bolt is not lapped to the teeth of the barrel extension. It could simply be a case of working it in by hand (sit it in your lap and pull it out of battery an inch and let it go a hundred times while watching telly). Or, if the barrel extension lugs are not perfectly lined up then there will be too much friction as the new bolt goes in unless it has plenty of momentum.

                      I read Wolf 100 is lacquered steel cases from Russia whereas Wolf 120 is brass made by Privi Partizan in Serbia. Is this right? You guys would know. If so then slightly different ammo dimensions and pressures suggest it is on the edge of working, so not catastrophic.

                      Ejecting at 5pm usually means it is at the lower end of cycling energy. A heavier buffer will not help in this situation.

                      Does it lock back properly on the last round? On the face of the bolt and not the carrier?
                      Correct on all points Sir.
                      Life member NRA, SAF, GOA, WVSRPA (and VFW). Also member WVCDL. Join NOW!!!!!
                      We either hang together on this, or we'll certainly HANG separately.....

                      Comment

                      • southern180
                        Bloodstained
                        • Feb 2015
                        • 57

                        #12
                        My AA upper/PSA lower did the same when new, I used lots of lube at first due to the surfaces being very rough, almost like 600 grit, as for the 5 o'clock eject thats your lower end timing, my fix was a JP silent cap. buffer spring. Spring made all the difference and I can change springs with different set ups,,, Lube and keep firing it will get smothe and lapped in, My has seen 6-700 rounds of all the types of import ammo ,feeds them all

                        Comment

                        • montana
                          Chieftain
                          • Jun 2011
                          • 3209

                          #13
                          Originally posted by blofeld42 View Post
                          I usually have the rails somewhat dry, but I'd prefer that it work with enough margin even if not well lubed, and it's failing somewhat consistently. This cropped up after about 60 rounds.

                          What does radiusing the ejector do?
                          The AR platform should be well lubed especially when breaking in a new rifle. It is a myth that you should never use too much lube in an AR rifle. My rails are well lubed as is my bolt,trigger assembly, recoil spring and charging handle.



                          Last edited by montana; 08-30-2015, 02:53 PM.

                          Comment

                          • Klem
                            Chieftain
                            • Aug 2013
                            • 3507

                            #14
                            Originally posted by montana View Post
                            The AR platform should be well lubed especially when breaking in a new rifle. It is a myth that you should never use too much lube in an AR rifle.
                            +1

                            If it started after 60rds then the thin coat from the shop has worn off.

                            AR reliable cycling = lube
                            New parts, micro gritty, AR reliable cycling = LUBE.

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