Grendel brass ejection angle

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  • arizona98tj
    Bloodstained
    • Feb 2013
    • 47

    Grendel brass ejection angle

    I'm aware of the diagram describing issues you may have with an AR platform rifle based on where your spent brass lands. So....here is what I'm seeing.

    I've tried 3 brands of powder (CFE 223, Benchmark, & A2230-S Data). I'll focus on the 123 gr A-Max bullet for this example. Brass is brand new Lapua with a COAL of 2.250".

    1. With all powders EXCEPT CFE 223, the brass lands about 10' out, in the 3:30 to 5:00 zone. The velocities are hitting around 2550 to 2600 FPS.

    2. With CFE 223, the brass drops into a nice neat pile at about 1:00 to 1:30, some 8' away.

    I'm seeing no indications of excessive pressure with the CFE 223 loads. The group, using 31.2 grains, is sub-MOA, @ 2600 FPS, with an SD of 10.0 FPS. I'm using a CCI 450 mag primer.

    According to the diagram and my brass landing between noon and 3:00, I'm seeing an over gassed situation. I'm using an Alexander Arms 24" Overwatch upper.

    According to Hodgdon's own burn rate chart, Benchmark is quite a bit faster than CFE 223. I've also used BL-C2, but didn't comment in my range notes where the brass was landing so won't include it in this discussion. I don't recall it being in the same landing spot as the CFE 223 brass but can't swear to it.

    Anybody got an explanation as to why this is happening? This is not a one time thing....I see this every time I use CFE 223 in the Grendel.
  • Drifter
    Chieftain
    • Mar 2011
    • 1662

    #2
    It's the difference in the burn rate of the powders. CFE (& LVR) are considerably slower burning compared to other powders typically used in the Grendel. Thus, more powder is used (such as ~31gr of CFE versus ~27gr of Benchmark for 123gr bullets). You might notice a difference in recoil too.
    Drifter

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    • arizona98tj
      Bloodstained
      • Feb 2013
      • 47

      #3
      Thanks....much appreciated.
      Last edited by arizona98tj; 09-06-2014, 05:34 PM.

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      • NugginFutz
        Chieftain
        • Aug 2013
        • 2622

        #4
        The brass and powder are both defective. Box it up and send it to me. I'll safely dispose of it, 30 grains at a time.
        If it's true that we are here to help others, then what exactly are the others here for?

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        • arizona98tj
          Bloodstained
          • Feb 2013
          • 47

          #5
          Originally posted by NugginFutz View Post
          The brass and powder are both defective. Box it up and send it to me. I'll safely dispose of it, 30 grains at a time.
          Good idea, Grasshopper....go wait at your mailbox....it will be along shortly.

          Comment

          • sneaky one
            Chieftain
            • Mar 2011
            • 3077

            #6
            AZ -98 , trust Drifter on this issue.

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            • rasp65
              Warrior
              • Mar 2011
              • 660

              #7
              What I found with my Grendel compared to a 223 AR is that the case hits the ejection port and bounces towards 2 oclock when I checked the action in slow motion. Here is a video that had the same results: http://www.youtube.com/watch?v=YbXBDe1argo here is a video of a 223 AR: http://www.youtube.com/watch?v=xPwTGfhUulk

              Comment

              • sneaky one
                Chieftain
                • Mar 2011
                • 3077

                #8
                Did u ever see Uncle Ted run his AR @ full auto on his Spirit OTW show? The angle of deflection is mostly forward- say 2: 00. The shell deflector is real!!! Duh!!!!

                Tune it to your needs by , cutting 1 coil @ a time off of the ejector spring . Search abap on here. This site is being re built now, due to a hacker intrusion , from hell.

                (The hunt is on for the bad guy, he will show up via a trail of, I can't say . relax, re-sign in. You can send pm's while in -sign in mode. If in doubt , email Hanka.)

                I find a diff brass expulsion from my shorty 40= 5: 00 -to the rt rear== fine for me to gather up, near my shoot bench.
                Every gun will exhibit diff results .

                Comment

                • sneaky one
                  Chieftain
                  • Mar 2011
                  • 3077

                  #9
                  Rasp, you are correct on the frontal angle of most Grendel brass out of the chamber.,, yet it depends on the loads- lite pills, or the heavier units, & the charge wt.

                  My Grrr, runs them out @ about 3:00, using my tweaked Gmx loads at safe pressures. I park a small cardy board box near that area- all the brass lands inside it= sweet!

                  Other team members may report diff results.

                  Comment

                  • rasp65
                    Warrior
                    • Mar 2011
                    • 660

                    #10
                    S1 I have shortened my ejector springs using this method: http://www.gswagner.com/arejector/arejector.html then added a H3G buffer and have not had any ejection problems. I noticed looking at the slow motion video of before those mods the cases were thrown 3:00 to 4:00 AM. So I take back what I said before about the timing but the cases still hit the ejection port before they hit the deflector.
                    Last edited by rasp65; 09-11-2014, 12:29 PM.

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