New Grendel owner ammo question

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts
  • kedenver
    Unwashed
    • Feb 2018
    • 4

    New Grendel owner ammo question

    So being new here I posted this in the Hunting Forum by mistake and am posting it here also

    SO this is my first post..been watching and learning the last few months and finally took the Grendel plunge. I build my first upper, I have built many lowers. I used a Odin works barrel kit and when I test fired the first time, I got the bolt to lock back but no ejection..the case was just laying loose on top of the mag....I thought well new bolt and carrier maybe it needs some breaking in. Well after 10 shots all locked the bolt but no ejection. I was using American Eagle 90 grain. I had some Hornady Black and tried them, function was flawless ejection at 4 o'clock, zero issues. So since I reload I looked at the brass and the rim on the Eagle appears to be thinner. So I am asking have other shad this issue. The Hordany rim appears to be noticeably thicker and am thinking the ejector may not be holding the case long enough for ejection but enough for extraction. Any help is greatly appreciated.
  • grayfox
    Chieftain
    • Jan 2017
    • 4295

    #2
    Welcome to the Horde!
    There are possibly some issues that arise around over/under gassing, gas block fit and such, but for a new rig I'd concentrate on finishing your break-in, esp since the Hdy black cycles ok. The Hdy black have more force (and kick) behind them since they are a heavier round, but before making any changes try to get about 50 down range of factory ammo first. Shoot, clean, shoot, clean... I shoot mine 1 shot at a time up to about 20, then maybe 2 at a time especially if there's been some ft-eject's like yours. Did you clean the chamber and throat area, are you running the bcg a little wet/oily (most folks recommend this for new builds) not just super-dry, what kind of barrel, bolt and bcg... etc?
    All those new moving parts need to break in and smooth each other out.
    ps, I don't use any steel ammo, particularly not for the breakin.
    One more point, anything noticeable about the brass, soot, cloudiness on the sides, etc?

    The one Grrr that I had most of the same things with, after 50 rounds everything smoothed out and it's been rockin' ever since.

    I like those 90 AE's, wish they were still in stock (the 50/box) somewhere.
    "Down the floor, out the door, Go Brandon Go!!!!!"

    Comment

    • VASCAR2
      Chieftain
      • Mar 2011
      • 6219

      #3
      You didn’t mention which Odin barrel kit you used. Odin sells several different length barrels and with 6.5 Grendel the 18” barrels can do peculiar things. Odin uses an intermediate length gas system with their 18” barrels. You didn’t mention if your using an adjustable gas block. With a fixed gas block the light 90 grain TNT might not be giving enough pressure at an intermediate length gas port to reliably cycle. Use a lot of lube on a new build and as the rifle wears in the 90 grain TNT might start functioning. If you didn’t bed the gas block you might be getting a little leakage. Usually minor gas seal leaks seal off with carbon after a few rounds which can improve functioning.

      This is all speculation so if the problem persists give the specific information on barrel length, gas system length, type of gas block, buffer and buffer spring used in your build. Each item can affect the specific function on an AR-15.

      Comment

      • LRRPF52
        Super Moderator
        • Sep 2014
        • 8569

        #4
        Sometimes new extractors are really sharp on the corners of the extractor lip, and this will hold onto the case longer than is ideal for reliable ejection, even with the ejector doing its job.

        Also, to rule out gas system issues, is the bolt locking back on the bolt face, or is the bolt carrier face catching on the bolt catch?

        In my Lilja 318 MLGS Grendel, I got reliable cycling with factory AE 90gr TNT. Its fast too, and actually quite accurate.

        Alexander Arms used to make a factory 90gr TNT load, but it was very finicky in different rifles due to the gas system being more ideal for 100gr and up, so they discontinued it. 90gr TNT uses faster-burning powder, punting the bullet out, as opposed to your medium-slow powders that Grendel normally uses behind 120-130gr. Especially on RLGS with a large port, the 90gr TNT can be hard to drive the gas system.
        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

        • kedenver
          Unwashed
          • Feb 2018
          • 4

          #5
          Thanks for welcome....so the bolt carrier is well lubed.....with the 90 Federals I am getting extraction from the chamber and the bolt is locking back..so its getting enough gas...the issue is ejection is not happening the case is just laying on top of the mag loose...like its slipping out of the bolt face after extraction from the chamber. The Hornady functions flawless,,,,,good extraction, ejection as 4 o'clock and bolt lock back. The rim as I stated looks to much thinner and I am thinking its not thick enough for the extractor to hold on tight enough for ejection.

          Its an Odin 18 inch barrel with non adjustable gas block....
          Last edited by kedenver; 02-20-2018, 10:35 PM. Reason: missed answering a question

          Comment

          • grayfox
            Chieftain
            • Jan 2017
            • 4295

            #6
            One other possibility is the extractor spring/o-ring... guys have either changed out the o-ring, or removed it, or replaced the whole o-ring/spring combo and that could help. But again, I wouldn't recommend it until after you've got 50+ rounds down range.

            On the lock-back, like '52 was asking, look to see if it locks back on the carrier face (not enough), or on the bolt face (where it's supposed to lock). They look kinda similar at a glance.

            Federal AE 90's work in lots of barrels (and in all of mine) so I wouldn't worry on the case rim too much.
            "Down the floor, out the door, Go Brandon Go!!!!!"

            Comment

            • bj139
              Chieftain
              • Mar 2017
              • 1968

              #7
              Remove the o-ring from under the extractor. I have done that on several ARs and they function fine.

              Comment

              • easterneag
                Bloodstained
                • Oct 2014
                • 28

                #8
                Have had issues with AE 90 grain in mine. These rounds will eject and bolt will lock back though, but barely, they just barely flopp out about 2 inche's and land on the bench next to the rifle. Hornady Black and SST eject fine out to about 5 or 6 six feet away with bolt hold back. I'm runnung a 18 in AA Lightweight barrel with an AA hard use bolt and a Superlative adjustable gas block and a low mass bcg. Haven't tied Federal Fusion yet.

                Comment

                • BCHunter
                  Warrior
                  • Jan 2018
                  • 555

                  #9
                  FYI op Odin sends a tunable gas block in their barrel kits. It should have a set screw on the side and a adjustment nut on the front. This allows you to tune your gas system and then lock it down. So you should have the capacity to adjust your gas system already.

                  "Adjustable" gas block is an upgrade that has a dedent to quickly change the gas system. For adding or removing a suppressor.

                  Comment

                  • kedenver
                    Unwashed
                    • Feb 2018
                    • 4

                    #10
                    BCHunter I do not have an adjustable gas block....no set screw, or nut just a plain low profile gas block..

                    by139 I will remove the o ring and try that my next trip out....altho I don't see how that will help...but hey willing to try and see what happens.

                    Maybe after the first 50 or so rounds it'll start working...if not I'll just get some 90 gr pills and reload my own...

                    And the bolt is locking back correctly

                    Comment

                    Working...
                    X