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Too much headspace on new AR15 build

Discussion in 'Build it Yourself' started by insomniac, Sep 6, 2019.

  1. insomniac

    insomniac NES Member

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    I'm a newbie to the AR scene. I've been VERY slowly acquiring the parts to an AR (over years!), and am finally getting to the finish line of my Frankenstein build. USGI contractor upper. Boise Tactical milspec M16 BCG. Wyndham Weaponry 16" 5.56 barrel w/ carbine length gas tube. My father-in-law helped me out with part of the build (yes I did launch and lose a takedown detent), and we finished the upper, but head spacing was odd.

    He used a pair of Clymer .223 gauges, but didn't bother removing the ejector and extractor. It closed on both the go and no go gauges, but he figured it was fine to test.

    We took it to the range and on one of his rifle length lowers we tried the upper and fired individual rounds. The cases looked fine - didn't show any signs of cracking or strange wear patterns. However, with a full mag, the rounds weren't cycling properly, requiring a manual cycle to load the next round.

    I took it home and decided to redo the headspacing test, so picked up a pair of Clymer 5.56 gauges, a bolt vise, and a set of punches, because I figured I should remove the ejector and extractor and re-test. Nope - still closes on both the go and no-go gauges.

    So now I feel like I have a problem of too much headspace on a new build, and am not sure where to go from here. Find a local gunsmith? Take apart the upper and redo everything?
     
  2. jayhitek

    jayhitek NES Member

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    I think bringing it to a local gun smith is a good idea.
    Try Tim that works out of Gartman arms.
     
  3. insomniac

    insomniac NES Member

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    Yeah, that's kind of what I'm thinking, though I was hoping someone would say it was something simple or a common problem.
     
  4. jayhitek

    jayhitek NES Member

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    You said it's a 556 barrel but running 223 ammo... What happens when you put in a 556 go/no go gauge?
     
  5. insomniac

    insomniac NES Member

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    It closes on both gauges. Since it's a new barrel (and the bcg wasn't matched) I figure I may be out of luck and may need to just buy a new BCG.
     
  6. Warm_Garand

    Warm_Garand

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    Failure to cycle is lack of gas--or maybe just using an improper buffer configuration, like you are.

    You need a CARBINE buffer and a CARBINE spring to test your upper.

    If the rifle still won't cycle with a carbine buffer, check your gas block. Are you SURE the gas port is properly aligned?

    Have you got a different bolt carrier group to swap in?

    The gas key COULD be leaking--but I'd guess the first culprits are buffer, then gas block.
     
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  7. Warm_Garand

    Warm_Garand

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    Headspace problems on AR15's are pretty rare, and bolts don't need to be "matched" to barrels. The parts are either in spec or they aren't. It is POSSIBLE that your bolt isn't in spec. I'd expect a Windham barrel to be 100% good to go.

    No need to spend more money just yet.

    Take it in logical sequence, addressing the known non-spec components first.

    Get yourself a carbine buffer and spring. No function? Swap bolt with a known good spare. No function? Tear the front end down and check the alignment on the gas block.
     
    Last edited: Sep 7, 2019
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  8. SKumar

    SKumar NES Member

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    Did your gas system come assembled with the barrel, or did put it together from scratch?
     
  9. Uzi2

    Uzi2 NES Member

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    I'll take gas block problem for 800 Alex.

    As noted above, headspace problems are extremely rare on AR15s. They are one the most "interchangeable parts" rifles ever made.
    Check for signs of gas leakage at the gas block and gas key on the bolt.
    Check the gas rings on the bolt.
    Check to see if the gas block is aligned correctly over the barrel gas port( make sure the gas port is clear too and not fouled with carbon or copper)....it could have moved if its a bolt on type and coukd have been installed and pinned incorrectly if its a pinned type.

    If your brass looks fine, its not a headspace issue.
    If its not cycling, its a gas issue.
     
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  10. insomniac

    insomniac NES Member

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    Thanks for the feedback all!

    I was wondering if the rifle lower might have contributed to the cycling problem which is why I mentioned it. The FSB was already mounted to the barrel, but I did attach the gas tube myself. I'd also agree that things are in spec or they aren't - which is why I'd use the headspace gauges to check and am worried they're not. Unfortunately it's my only bolt right now, so I can't easily swap it out.

    I'm alright with testing the thing on the firing range more once I finish the build; I'm just wondering if it's safe to do that if it's failing the no-go check on a brand new build.
     
  11. mac1911

    mac1911 NES Member

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    how did you check head space?
    How did you manipulate the bolt?
    call windham and ask what reamer they use on their barrels.
    Then find out what the manufacture cuts their reamers to.

    Then pick up a field gauge and retest your headspace.
    I will almost say with certainty that manufactures are not leaving their chambers on the min side of specs.
    get or borrow a 5.56 NOTO field or max head space gauge
    Max nato is 1.4736" clymer nogo nato 5.56 is 1.4696" so you can already see some differences there in gauges.
    Gauges and reamers from manufacture to manufacture differ also. Fun stuff.
    Do you have provisions to test your cartridge headspace demensions on a factory unfired case vs a fired case?
    Dont get to hung up on headspace just yet.

    Also as far as I know the "go" demensions for 223/556 are the same 1.4636" although AFAIK there is no such thing as a NATO " no go " gauge theres just a 5.56 NATO "MAX" 1.4736" vs 223 field at 1.4696" <which is what clymer uses for "their" max 5.56 gauge.
    Fun stuff.

    Even more fun. I took a quick look at WW they have barrels listed as 223 and 223/556 but I did not see any thing in the descriptions explaining any difference.
    i think for the most part AR barrel manufactures are leaning on a chamber reamer closer to a Wylder 223 spec than "NATO".

    View: https://www.youtube.com/watch?v=pcVh-XBOLKg
     
    Last edited: Sep 7, 2019
  12. mac1911

    mac1911 NES Member

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    You got this far with out a gun smith , if you go to a smith make sure to bring your gauges in case they dont have them.
    Honestly though I think you can do it and get this rifle straight with out paying someone.
     
  13. Warm_Garand

    Warm_Garand

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    Just to clarify--I have carbine uppers that will cycle just fine on an A2 lower/rifle length buffer tube/buffer/spring. Those uppers are also pretty much over-gassed. Your upper may have a more conservative gas port diameter, and that is why it needs a carbine spec buffer system and will fail to cycle on an A2 buffer system.

    Try to blow air through your gas tube, just so you know there aren't any obvious obstructions. Brake cleaner or WD-40 with a straw which will fit into the buffer tube will also work.

    You didn't mention what kind of ammo you were shooting.

    If the action partially cycles, as in almost, the extra oomf of a true 5.56 NATO spec cartridge (XM193) might provide the extra gas pressure to get the rifle cycling. (ETA: Assuming the rifle is chambered for 5.56 NATO, as this one is).
     
    Last edited: Sep 7, 2019
  14. mac1911

    mac1911 NES Member

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    even some of the most mild 223 out there should be producing enough mmphh to cycle a AR. even a rifle length with a carbine buffer set up.
     
  15. Mountain

    Mountain NES Member

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    My 2 cents...

    First, what ammo? Have to ask...

    Cycling almost always a gas problem. Also be sure it's well lubed. Try a different mag too.

    Might be easier to just buy a bolt from Windham and call it a day regarding the headspace issue. A 5.56 field gauge is a good idea, however.
     
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  16. insomniac

    insomniac NES Member

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    The ammo was commercial .223, so yes - less powered. I'd think it'd still cycle a rifle buffer and spring, but I'm new here.

    I was trying to avoid buying more hardware, but maybe this will just encourage me to build a second.

    NOOOO, is this how EBR disease starts?
     
  17. Supermoto

    Supermoto NES Member

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    .223 will cycle a rifle buffer and spring.

    Did the rounds eject at all when you were testing? If not, where they left in the chamber? Did the bolt cycle but not pick up the next round?
     
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  18. insomniac

    insomniac NES Member

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    With one round loaded, the spent casing ejected. (This was done a couple times.) Multiple cartridges in a magazine were not cycling. In those instances the charging handle needed to be used to cycle the spent case out and load the next round.

    At least, that's how I as remembered it; this was back in July. I'll probably need to actually finish this rifle to test more.
     
  19. mac1911

    mac1911 NES Member

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    I would start from square one and recheck everything you did.
    I can only say is look closely.
    Theres usually something amiss with the gas system . My buddy did not install his gas tube retaining pin causing all sorts of fun issues.

    Im a minimal lube type. If its not functioning with out a lot of lube something is wrong. Now fine if you want to run it wet after its up and running thats ok
     
  20. Supermoto

    Supermoto NES Member

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    With one round loaded, did the bolt lock back?
     
  21. milktree

    milktree NES Member

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    5.56 and .223 ammo have identical external dimensions.
     
  22. akma

    akma

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    If you have access to a Hornady headspace comparator you can check to see if there's too much headspace. AR's can be finicky with a frankenbuild. You need to sort it out.
     
  23. insomniac

    insomniac NES Member

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    I don't remember if the bolt locked back with a single round, unfortunately.

    So to summarize this thread:

    - Go to a gunsmith, but also don't and try to figure it out yourself
    - Headspace shouldn't be a problem so you shouldn't need to check it, but also can be problem, so definitely check it
    - A carbine gas system with rifle buffer might be a problem, but also shouldn't be a problem
    - Contact the manufacturer
    - Buy a new bolt
    - Fix the probably wonky gas system

    I know in the end I have to make my own damned decisions, and appreciate all the opinions. I just find it funny how contradictory they can be. I was hoping someone could say this thing were safe to test fire, but no one can actually tell me that, and I shouldn't trust the opinions of random people on the Internet for safety.

    Side note on Clymer headspace gauges: their .223 and 5.56 NOGO gauges are different! I don't think they should be, but they are. 5.56 is 1.4696, whereas .223 is 1.4666. For NATO gauges Forster seems to only offer the GO and MAX (which I take as field gauge) these days.

    I've decided that I probably should:

    - Finish my build finally, and register the damn thing
    - Get a field gauge, and make sure it doesn't close on that
    - Work on the cycling problem
    - Find a gunsmith if I can't figure it out

    Thanks for everyone's time!
     
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  24. SgtHal75

    SgtHal75 NES Member

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    This.... I bet it’s gas block or tube not installed properly.. check that and see, it’s happend to me before.
     
  25. SgtHal75

    SgtHal75 NES Member

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    If Winchester white box, throw it all in the live ammo container at the range, Get rid of it!
     
  26. mac1911

    mac1911 NES Member

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    So you have a 16” upper , presume carbine length not a mid length
    Should cycle a A2 rifle buffer and spring no problem.

    Ammo- yeah there might be some crappy ammo out there buy I can tell you its amazing how “low” your ammo gas volume and pressure can be and still function.
    Playing with cast loads in a AR I was pretty shocked how low I could load H4895 and still get 100% function

    As far as your problems

    START OVER
    Clean and detail strip everything. Make sure everything is where its supposed to be and secure.

    Now as a base line pick up some M855
    Once you get full function you can try other ammo.

    I will repeat: You got this far , You can get there.

    Now if your frustrated and just want it DONE , find a gun smith

    When it comes to gauges/reamers/ parts
    There are differences from each manufacture.
    Windham does not help with their product descriptions. They have 223
    223/556 but no mention of what chamber they actually cut?
    I only have 3 ARs now and all have 223 wylde chambers
     
    Last edited: Sep 8, 2019
  27. jrpascucci

    jrpascucci NES Member

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    Here's a video of a guy whose WW barrel failed a no-go check. WW replaced it but apparently complained about doing so. However, maybe you got this guy's barrel.

    (A few more ideas - sorry if there are any dups, I scanned above posts but didn't read in depth)

    1) failure of a no-go is only if you don't need "excessive pressure" to get it in - and the 223 no-go may very well fail in a 556 when the 556 wouldn't, so if it's noticeably more tight on the 223, then it's probably okay. If it spins without significant constriction if you just put the bcg in a dismounted barrel, then, yeah, likely a problem.
    2) If you have a friend/range mate with an AR, give your BCG a try in their barrel to see if it's that: no go gauge their bcg on their rifle, then your bcg on their rifle, then their bcg on your rifle.

    About the cycling:
    1) Did you see how far it comes back when it starts to cycle? If not, aim downrange into a berm, and move your head to watch it cycle - how far is it coming back? Is it nearly enough to eject/strip, or barely moving?
    2) If you extend the bolt and stand it on the bolt face, does it stay out, or just collapse? If the latter, replace your gas rings.
    3) Are the breaks in the gas ring lined up at all? Don't do that.
    4) Is there any play in the gas tube? Is it possible the gas tube pin is the wrong size?
    5) Is there any damage/wear to the end of the tube that interfaces with the gas key? is the gas key staked, and/or did you stake the gas key yourself? If there is no staking, is there any play in the gas key screws (should be 57 inch-lbs torque, which is really very tight)?
    6) If there is staking or the above is okay, spray some oil on the edges of the interface between key and bcg and push compressed air through it: any bubbles detected are a problem. You could lap the two faces (on the bcg and on the key), but be careful not to go too far to avoid shortening the key rise: barely remove any material and then use green loctite (626) as a gasket (remove any loctite that gets inside the bcg or inside the screwholes). I understand one doesn't use loctite on these screws, for some reason I don't understand: staking is the way to go.
     
  28. KMM696

    KMM696 NES Member

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    Most grades of Loctite break down with heat, and the rifle is dumping hot gas through the gas key nicely heating those two screws. Staking isn't temperature dependent, and also gives a visual indication on whether those screws have backed out at all. In addition, both parts deformed by staking are replaceable and relatively cheap. The highest service temp I could find for a Loctite threadlocker is 400F, which would probably work - I've never measured gas key temps during shooting. The first indication of a threadlocker failure would be the screws backing out, and I guess I consider the gas system critical enough to stake it and not have to think about it other than checking the staking when the BCG comes out.
     
  29. jayhitek

    jayhitek NES Member

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    Glad we could help!! [rofl]:)
     
  30. jayhitek

    jayhitek NES Member

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    I believe the Red loctite is the one you want for heat resistance. Blue is the best all purpose one when it comes to places on the AR that aren't sitting on the barrel.
     

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