My Striped Grendel

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  • bj139
    Chieftain
    • Mar 2017
    • 1968

    My Striped Grendel

    I have been assembling a Grendel from a 16" BCA barrel and bought an AA Overwatch in the meantime.
    GrendelsIMG_20170703_142327 (Medium).jpg
    The Overwatch is precise enough with Wolf steel, Hornady SST and AMAX.
    IMG_20170703_140314 (Medium).jpg
    The 16" BCA barrel finally showed acceptable precision with AMAX factory ammo only.
    IMG_20170703_140422 (Medium).jpg
    Yesterday, I started resizing Grendel brass for the first time and noticed something strange.
    Guess which brass was fired in the BCA barrel sidecharger and which in the Overwatch with brass deflector?
    IMG_0007 (Medium).JPG
    Finally, some dummy rounds with 85G Sierra bullets which I loaded into 6.5X55 in the 1980's.
    I haven't decided on a powder to try for the Grendel.
    IMG_0012 (Medium).JPG

    Until my last time at the range with the BCA Grendel, I was firing rounds without a gas block and just mortaring out the rounds with the side charging handle. It was easy against a solid wood bench. What are the implications of the stripes? Should I contact BCA for a return or just keep this oddity? It operates fine in both manual mode and gas operated mode. Would a smoother chamber make it easier to manually eject a fired round? Does anyone here have any experience with this? I live in Pennsylvania which still does not allow deer hunting with semi-autos so it must be manually operated.
  • NugginFutz
    Chieftain
    • Aug 2013
    • 2622

    #2
    bj139,

    Nice looking pair of boom sticks, and thanks for posting up your progress with that BCA tube.

    Re: the 85 grain Sierra HP Varmint's. I've found that H322 worked wonderfully, with superb accuracy in a gun that has proven quite finicky about most other loads. My best accuracy node was at 28.4 grains. I'm fairly sure that IMR8208XBR would work pretty well, also, but H322 was one of my magic .243 powders in that bullet weight range.

    The spent brass from that BCA is troubling, though. Those rings are clearly abnormal, and can't be doing anything good for your brass life. Further, while working with an adjustable gas block on one of mine, I started with the gas completely shut off. At no point did I ever have difficulty extracting spent cases. This makes me think that the rings you have may be having the effect of "locking" the brass in place.

    I remember reading one or two other reports about rough chambers from BCA. IIRC, one owner was in contact with BCA, and had reported that they recommended having the chamber refinished. Whether or not you send it back to BCA, I would definitely have that chamber touched up with a finish reamer before sending too many more rounds through it for imprinting.

    ETA: Rather than shooting without a gas block, I suggest blocking the gas port by either using a tubeless GB rotated so as to block the port, or getting an adjustable and shutting off the gas. It just feels bad to imagine hot gasses exiting so small a hole under such great pressure.
    Last edited by NugginFutz; 07-04-2017, 10:36 PM.
    If it's true that we are here to help others, then what exactly are the others here for?

    Comment

    • bj139
      Chieftain
      • Mar 2017
      • 1968

      #3
      NugginFutz,

      Thanks for responding.

      I will take your suggestion of H322 for the Grendel since the Lee load data I got with the dies lists it for 85g up to 123g bullets and it seems to be the most efficient powder per unit weight

      I will contact BCA to see if they will replace the barrel. If the brass were to separate at the rings, another round shouldn't chamber but if it did I wouldn't want to be around. The rings appear to be ridges. I can feel no grove inside with a dental pick.

      Initially, I envisioned a jet of gas burning a hole in my carbon fiber hand guard so I had the gas block turned around so the holes did not align. After I was planning to get the gas working, I just decided to "wing it" and shoot with no gas block. The hand guard shows no evidence of damage, maybe a slight powder burn.

      I just tried to cycle the dummy rounds through the BCA and the bullet stuck in the lands. It was pulled from the case on ejection. I had to knock it free with a cleaning rod. The 85g bullets are fatter near the nose than the Wolf steel 100g bullet. I guess the SAAMI chamber is tight.
      Last edited by bj139; 07-04-2017, 07:17 PM.

      Comment

      • VASCAR2
        Chieftain
        • Mar 2011
        • 6219

        #4
        I think I would contact Bear Creek Armory and send them the photo of your brass. I'd also let them know about your erratic accuracy. Your AA barrel seems consistent, BCA doesn't. At BCA price point it's not surprising the quality may vary from barrel to barrel.

        Comment

        • NugginFutz
          Chieftain
          • Aug 2013
          • 2622

          #5
          Originally posted by bj139 View Post
          I will take your suggestion of H322 for the Grendel since the Lee load data I got with the dies lists it for 85g up to 123g bullets and it seems to be the most efficient powder per unit weight
          You may wish to consider the purchase of the official Grendel Reloading Handbooks. (Check AA's website or LRRPF52's signature for a link to AR15Buildbox.com or something like that.) They are truly a fount of information about anything you can imagine about reading this round. The authors went the extra mile: Their collaborative effort included pressure testing, terminal ballistics testing, etc. The books contain information you will never get simply by googling recipes from unknowns like myself. Further, while I can offer the customary (but seldom regarded) warnings about starting low and working your way up, etc., the bottom line is my barrel likes what it likes, and yours has its own particular wants and needs.

          Originally posted by bj139 View Post
          I just tried to cycle the dummy rounds through the BCA and the bullet stuck in the lands. It was pulled from the case on ejection. I had to knock it free with a cleaning rod. The 85g bullets are fatter near the nose than the Wolf steel 100g bullet. I guess the SAAMI chamber is tight.
          This particular bullet likes to be seated short; partly because of the large meplat and partly because of the length of the bullet. Mine are seated at 2.210", and shoot groups at or under 1/2 MOA. If you seated longer than 2.240" (Hodgdon's recommended seating depth for the 85 Sierra HP), I suspect you're going to stuff it into the compound throat or lands.

          IIRC, seating that bullet any longer would leave less than a caliber's worth of bullet seated inside the neck. (This is something I try to avoid with all projectiles - especially those with boat-tails - because it doesn't leave enough bullet shank in contact with the case mouth.)
          If it's true that we are here to help others, then what exactly are the others here for?

          Comment

          • LRRPF52
            Super Moderator
            • Sep 2014
            • 8569

            #6
            Those rings are very odd. I've never seen that before. Looks like the result of a burr during reaming that spun around and gouged 2 rings up near the shoulder.
            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

            • bj139
              Chieftain
              • Mar 2017
              • 1968

              #7
              I didn't get a chance to contact BCA today. I went shooting the 6.5 Grendel Overwatch and a 300 Blackout upper instead.
              I finally got a sub one MOA 5 shot group from the Overwatch while shooting factory Hornady AMAX.
              There are 4 shots in 0.38 MOA with a flyer to the upper left for 0.7 MOA total.
              The 30 cal holes are from the 300 Blackout.
              IMG_20170705_204324 (Medium).jpg
              The Blackout was shooting all over the place and I almost wrecked the Overwatch group by overprinting.
              After, I was cleaning the barrel on the 300 Blackout when the scope slid on the rail. I then loctited the base screws.
              I have to remember to always loctitite base screws and perhaps ring screws as well.
              Last edited by bj139; 07-06-2017, 02:38 AM.

              Comment

              • bj139
                Chieftain
                • Mar 2017
                • 1968

                #8
                I emailed Bear Creek Arsenal yesterday about returning the barrel. Still waiting for a reply.

                I started reloading the Hornady once fired Grendel brass. Some was over 1.520" in length after resizing so I decided to trim to 1.512". I seated some bullets without powder and made sure they cycled fine through the rifle without the bullet sticking in the lands as they had previously. They cycled fine. The COL was 2.123" with Sierra 85g HP bullets. I bought some HP335 and weighed the powder charge thrown by the Lee dipper to be 25.0 grains. The powder dipper chart shows 24.8 grains from that dipper. They are primed with federal small rifle primers (#200) and ready to add powder and seat bullets. The next dipper size throws 29g of powder. I think the max load is around 32g but I just want some easy shooting ammo so I will try the 25g. I have 16 rounds ready to finish. I may get to the range today if the rain stops.
                Last edited by bj139; 07-07-2017, 07:01 PM.

                Comment

                • bj139
                  Chieftain
                  • Mar 2017
                  • 1968

                  #9
                  I just got back from the range and made it an all Grendel day.
                  First the 16" BCA barrel.

                  IMG_20170707_150326 (Medium).jpg

                  I decided to play a tracking game with turret changes as indicated. The SWFA scopes sure do track well. 10X on BCA and 16X on Overwatch.
                  People said the 16X was too much power but I think 10X is too little power for the Grendel. 16X seems just right. I would like to try a 20X.

                  The BCA barrel produced 1.25 and 1.0 MOA three shot groups.
                  I will take it stripes and all.

                  Then the Overwatch upper. This thing is boring. It is obviously a much better barrel than the BCA.
                  It is no effort getting it to shoot well.

                  IMG_20170707_150346 (Medium).jpg

                  16 shots total, all I reloaded. Time to fill them up again.

                  Comment

                  • bj139
                    Chieftain
                    • Mar 2017
                    • 1968

                    #10
                    Still no reply from Bear Creek Arsenal about returning the barrel. I re-sent the email yesterday.
                    The last time I emailed them about an order they responded within 2 hours.

                    This will affect my decision to buy from them in the future.

                    Still, accuracy from the BCA barrel is now acceptable at a bit larger than 1 MOA with 85gr Sierras.
                    About what I would expect from a $100 barrel.

                    Time will tell how this affects brass life. The striped brass has been reloaded one time.

                    Comment

                    • VASCAR2
                      Chieftain
                      • Mar 2011
                      • 6219

                      #11
                      I'm old school I'd call BCA and ask to speak to customer service or tech dept.

                      Comment

                      • bj139
                        Chieftain
                        • Mar 2017
                        • 1968

                        #12
                        I shot the BCA 16" Grendel barrel today and saw my first sub MOA 5 shot group (0.905").
                        These were the same load I listed above with a dipper full of HP335.
                        IMG_0001 (Medium).JPG

                        It doesn't like the factory SSTs as much (1.445").
                        IMG_0005 (Medium).JPG

                        Keep or return?
                        Last edited by bj139; 07-19-2017, 01:42 PM.

                        Comment

                        • Mytie
                          Unwashed
                          • Jul 2017
                          • 12

                          #13
                          I've gotten rings like that on my brass from using a Lee chamfer tool. I can't tell in the picture. You've got me worried now. I just started my first 6.5 Grendel build. I ordered a ar-Stoner barrel from Midway. I've read that BCA makes the 24 inch Grendel barrel.

                          Comment

                          • dreadpirate
                            Bloodstained
                            • Apr 2017
                            • 29

                            #14
                            I like the idea of putting backup sights at 45 degrees just in case the boar (or whatever) decides to charge you!

                            Comment

                            • bj139
                              Chieftain
                              • Mar 2017
                              • 1968

                              #15
                              Many years ago I had a buck running by me when I had a Contender pistol with a 4X scope. One pointed shot was all I got.
                              With a 10X scope on my Grendel the same thing could happen so the quick tilt sights might be useful.

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