Project Grendel - Take Two

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  • Project Grendel - Take Two

    Last year I finally took delivery of the Zastava based Grendel I had been planning for a few years. Unfortunately, Project Grendel (Uno) failed due to the barrel supplied by PacNor. I cannot complain about the PacNor customer service, they agreed to replace the barrel within 24hrs of being notified and they went above and beyond. The original barrel I ordered was a simple #3 profile, they supplied as a replacement a Ruger "A" profile barrel, polygonal rifled, pre threaded and chambered in 6.5/06 - a significant upgrade.

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    Why not go with a PacNor again? Well I had already ordered a #2 profile Lilja that would exactly match the #2 Lilja on my 6/223. Two rifles that are externally identical was the idea.

    Anyway, when I went to pickup the Grendel, I also picked up two other builds - the completed 6.5/06 and the 6/223 with it's new barrel. So I had a busy time running in barrels for a little while. The 6/223 came good straight away, printing a sub 0.5MOA group with the running in load. It continues to shoot brilliantly today, putting 55gn NBTs out at 3250fps, with 80gn Speers going downrange at 3080fps and printing dead on point of aim at 100m. Happy with that!

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    Action - Zastava m85, only modification is to the magazine follower
    Magazine capacity - 4, but 3 is comfortable
    Barrel - Lilja #2, 1:10 twist, 5 groove, 21in muzzle
    Stock - Basner High Tech Specialties from the US
    Scope - Meopta 6x42, now wearing a Leupold VariX-III 2.5-8
    Weight - 6lb, 6oz

    Anyway, the Grendel has taken longer to get working as there is SFA load data available for the Grendel in a bolt gun. As it's not an AR15 I can choose higher and different pressure curves not available to the AR15 shooter.

    I chose to run 100gn NBTs as the primary hunting bullet, with 108gn Scenars for paper punching. Well, it turns out I choked badly on my choice of barrel twist - I went with a 1:10 twist on the theory that I wouldn't be shooting anything over 120gn in the rifle. The 108gn Scenar is a very long bullet for it's weight and won't stabilise in the 1:10 twist - in fact it is marginal in a 1:9 twist. Making oblong holes in the paper at 100m was a clean giveaway to a stability problem. I also suffered from frustration with the 100gn AMAX - they simply don't get on with the barrel and whilst velocities are good, accuracy is shite - hovering around 1.5 to 2 MOA.

    A little early work with AR15 loads showed that there was heaps of room to go in the bolt gun. So I started off with BM1 - it ended up maxing out too early. Next up was BM8208, and that is the powder of choice. The Nosler load data suggests a maximum of 29gn of 8208 for 2745fps with very good accuracy.

    I've loaded it up to 32.5gn of 8208, reaping a muzzle velocity of 3040fps with sub-MOA accuracy. In order to keep the rifle working safely during summer, I've throttled the load back to 31.5gn of 8208 which delivers 2960fps.

    Accuracy is acceptable too.
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    That means that with a 1.5in high impact at 100m, it is 1.5in low at 200m. For my son this means I can tell him to hold dead on with any critter out to 200m and he will kill it. This load carries 1000fpe past 300m and will have a 10in drop at that range with the sighting I have outlined.
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    In the next month or so, I'll tear it down, sandblast, Cerakote the metalwork in Sniper Grey and LIC the fibreglass in Kyoti Tan so it conforms to my hunting rifle pattern.

    Updates to follow.

  • #2
    Adam, well done on the build, you've certainly got some nice new toys to play with! Bummer about the twist rate though; live and learn I suppose. The little Leupy would sure look more at home on that little rifle.

    I wouldn't mind doing something similar myself as all of my centrefires are full sized rifles in heavier calibres; none of them are less than 8.5lbs. Something like yours would be a great carry-all-day job in a light shooting calibre that I could let the kids use as well.


    • #3
      Bob, I'm thinking along a similar line, those little M85 actions are tiny and only around $350-400 new. I've seen some of the groups from Adam's 6-223 which is built along similar lines and around 6lb. It's a 1/2 MOA rifle.
      Guns don't kill people, Chuck Norris does.


      • #4
        Thanks for that.

        I built the Grendel for my kids to use as their primary hunting rifle. It is flat enough to make holdover irrelevant, light enough for them to carry all day, it hits hard enough that they don't need anything else and it is cheap to run.

        I know a lot of folks would use a 223 for this purpose but I don't think the cartridge has the power needed for me to be comfortable with it being a one shot killer. Nothing puts a kid off hunting more than the animal thrashing around and squealing after they have shot it. They like it to die cleanly and without fuss.


        • #5
          Adam, is there any reason the M85 as chambered in 7.62x39 could not be loaded to those same higher pressures ie higher than in the AR/AK platforms?


          • adamjp
            adamjp commented
            Editing a comment
            Can't see why you couldn't explore a higher pressure level in that case.

            Just be aware that when a primer pierces on these actions it can mean that the trigger sear gets slammed by the firing pin and will break. Any m98 trigger will fit the Zastava actions.

        • #6
          Been a big weekend in Project Grendel land.

          Grendelised a pig @ 71m on Friday afternoon and then Grendelised a Fallow buck this morning.

          Without including significant gory photos, here is a picture of the 100gn NBT which went through the nearside shoulder blade, performed a heart/lung bypass and piled up under the offside skin of the pig.

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          • #7
            Not a bad pig either.


            • #8
              FWIW the bullet weighed 52gn once I cleaned the pork off it.

              Today I changed scope to the simpler 6x Leupold and then proceeded to shoot this three shot group at 100m. Wish I could shoot this well all the time

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              and then immediately followed it up with a three shot group at 200m that went 0.75MOA.

              Next weekend, pull down and start of the Cerakote and stock painting which will keep me busy until Christmas.


              • #9
                So what's the latest. I wanna see that paint job!


                • adamjp
                  adamjp commented
                  Editing a comment
                  Cerakoting done.
                  Stock painting this coming weekend if I'm lucky.
                  New Talley Lightweights ordered to take the 6x36 Leupold I finally settled on.

                  It will be completed before Christmas (I've got two other stocks to paint, one to clear, two barrels and sundry items to Cerakote). The only thing getting in my way is the wife's "little jobs" and going hunting.
                  My son carried it all day on Saturday and didn't complain about the weight at all. That is a positive. Saw just under 20 Fallow (out of season) and didn't spot any pigs until just as we were driving out. Didn't get a shot off.

              • #10
                Gonna look great in the Talleys with the little 6x36 Leupy too. Fixed scopes are better for kids too I think, less temptation to muck around with the scope and fluff a chance at a shot.


                • #11
                  The stock is puttied up, a little sanding to go and it will be ready for painting. Once I had a guide coat of spray putty on there I could see a depression on one side of the stock that needed sanding back and refilling with fibreglass putty.

                  The Talleys have arrived, once the stock is complete I will swap the optic mounting system over. Unfortunately the LOW Talleys are still a few mm higher than my current setup, but they will be lighter.

                  I agree about the 6x scope. It will be simpler for the kids to use and will complement the self-imposed 250m maximum range of the Grendel nicely.


                  • #12
                    Since I've been a bit tardy on here lately with significant amounts of travel for work (BTW it sucks) I've not kept the thread up to date with Project Grendel Part Deux.

                    Cerakoted in Sniper Grey, stock in Coyote Tan, weighs 6lb 7.5oz with the 6x36 Leupold. Kills pigs without a problem and my young bloke is really happy to shoot it and carry it around. Short version is, he really likes it and can't see why a bigger rifle is needed.

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                    • bobnob
                      bobnob commented
                      Editing a comment
                      Originally posted by adamjp" post=72197
                      Since I've been a bit tardy on here lately with significant amounts of travel for work (BTW it sucks) I've not kept the thread up to date with Project Grendel Part Deux.

                      Cerakoted in Sniper Grey, stock in Coyote Tan, weighs 6lb 7.5oz with the 6x36 Leupold. Kills pigs without a problem and my young bloke is really happy to shoot it and carry it around. Short version is, he really likes it and can't see why a bigger rifle is needed.
                      Yeah looks good. What a nice balanced little rifle.

                      Hey it looks like a little brother to my stainless Zastava M70!
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