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My 2 new FAXON 5.56 AR-15 barrels are (too) overgassed ... sigh

Discussion in 'Rifle Country' started by GBExpat, Jul 13, 2018.

  1. GBExpat

    GBExpat Member

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    Surely ... this is not news to FAXON ... but I was blindsided. A very disappointing experience ... x2.

    Life. :)

    If only in their details/descriptions they included this information (and the required use of an adjustable gas block), I would/could have taken it into account while making my component/purchasing decisions ... and I would be making initial sights/optics decisions today.

    I reeeeeeeally like these 2 Uppers that I have assembled (as well as the GreenMtn Upper, mentioned in the email text below) and look forward to having this situation resolved.

    I will update after FAXON responds.


    =======[ email that I sent to FAXON last night ]=======

    @SUBJ: Overgassed? Issues with 2 of your Gunner barrels

    Hello. :)

    Recently I was bitten by the AR Building Bug (directly connected to deciding that it was time to enter the Free Floating Handguard World), something that I have successfully avoided for over a decade (my last two AR Builds were in 2004).

    I ordered a new-mfr 1:12 M16-Profile pencil barrel (for some lighter-weight-bullet action) from Green Mountain, which I received a couple of weeks ago, and decided upon two 1:8 5.56 Faxon Gunner barrels.

    You have no idea how much I have been looking forward to getting my two Faxon 5.56 Gunner barrels, a 20" from AR15Discounts and a 16" from Brownells.

    As with the GreenMtn barreled-Upper a week ago, after checking headspace on both Faxon-barreled Uppers I attached them to Lowers (20" with an A2 rifle stock & 16" with an M4-style collapsible) and headed into the backyard for a quick testfire on each. I only had 7 rounds left in the open box of the SouthAfrican M193 that I use so I fired 4 in the 20" and 3 in the 16" ... collected & segregated the cases and return to the house to inspect them.

    The 20" cases looked bad and the 16" cases looked HORRIBLE. The first thing that came to mind was unpolished chambers but I quickly discarded that thought as I thought it thru.

    It appears obvious to me that with both rifles the bolt unlocked before the pressure dropped to release the cases from the chamber walls, creating what are apparently drag marks on the cases.

    Is this what "overgassing" does? Causes an early unlock scenario and the extractor tries to DRAG the cases out?

    Here are 2 pics, this first of the Faxon chamber markings on my barrels:

    2v2JCzBGNxAW38L.jpg

    This 2nd pic shows 3 sets of fired cases. On the left are the 5 that I (test)fired in my GreenMtn rifle, in the middle, the 4 that I testfired in the 20" Faxon rifle and on the right, the 3 that I testfired in my 16" Faxon carbine.

    2v2JCzBnrxAW38L.jpg

    BTW, it does not show in the pic but the "drag marks" are also on the case shoulders of the Faxon-fired cases.

    Looking at those carbine cases (3 on the right) it crossed my mind that it was surprising to me that they managed to be extracted. Close inspection of the rims testified to the additional force exerted.

    I carefully cleaned the rifles and went back out to test fire again. The cases produced by the 20" were more of the same. The 16" only managed a single shot and then failed to extract, ripping off a chunk of rim with the effort.

    After thinking about it a bit, I cleaned the 16" again and mounted it on the A2 Lower to see if the heavier rifle buffer would make any difference. Nope. All I managed to do was get another FTEx with another chunk of rim ripped off (join me in prayers for the health of that extractor :) ).

    ---------------------------------------------

    So ... it appears that I have invested over $300 in my two Faxon barrels (and hundreds of dollars on components to build up rifles around those specific barrels) that, as it turns out, are overgassed (one severely, so) and, therefore, require the additional purchase and installation specialty adjustable gas blocks in order to be able to even use them. <sigh>

    Does that sound like a fair summary? :)

    S'funny ... I was greatly intrigued by those Superlative(?) adjustable gas blocks that you have on your website. They appealed the my Geek Gene. But the thought of spending $180 on adjustable gas blocks for ~$300 worth of barrels, especially when I do not use them in a way the needs the gas blocks to be adjustable was a No Go.

    Anyway ... my two new Faxon-barreled Uppers are safely tucked away in my north gunsafe until I can sort out this mess.

    I would like to hear your thoughts and/or advice on my situation and the accuracy (or inaccuracy) of my assessment of what is happening with these barrels. :)

    Thank you! I look forward to hearing from you!
     

    Attached Files:

  2. Mauser lover

    Mauser lover Member

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    Let us know how it works out. I'm kind of wanting to get one...
     
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  3. someguy2800

    someguy2800 Member

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    What are the port sizes on them and gas tube length?
     
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  4. Varminterror

    Varminterror Member

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    Most barrels, in general, are generously gassed, if not overgassed. Personally, all of my AR's have AGB's, so I wouldn't have it any other way.
     
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  5. GBExpat

    GBExpat Member

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    20" is rifle-length and 16", mid-length.

    No idea regarding the port sizes ... until after I remove the GBs to install the AGBs.
     
  6. LoonWulf

    LoonWulf Member

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    Not trying to give you static, but going forward use this as a learning experience. Best to check stuff like gasport dia, and alingment BEFORE installing everything.
    We all like to assume we're getting what we need when we buy stuff for our builds, and generally the suppliers like to provide what we want (that way we buys more stuff), but sometimes there are mistakes. Or sometimes one manufacturers specifications are such that they don't work with the other parts we want to use.
    The world of ARs is varied and interesting, but that also allows for issues at times.
     
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  7. GBExpat

    GBExpat Member

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    If the barrels that you are selling are overgassed to the point where adjustable gas blocks are required for the firearm to properly function, you should include that tidbit in the listed Details about the barrels. All I'm saying ... :)

    Prior to building these 3 I had 5 ARs all with non-adjustable gas blocks. They all run properly.

    The one that I just put together around that GreenMtn barrel, with its non-adjustable gas block, runs properly.
     
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  8. GBExpat

    GBExpat Member

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    Hahaha ... everything is a learning experience. :)

    While I was very disappointed yesterday, I am not upset with FAXON. I just think that, considering that they must be aware that these barrels are overgassed to the point of being unusable with regular gas blocks, they should inform their prospective customers. That doing so is just good business.

    It could be due to something as simple as them only thinking in terms of AGBs and giving zero thought to regular GBs. That could result in a blindspot for them reflected in the complete lack of information on this point.
     
    Last edited: Jul 13, 2018
  9. GBExpat

    GBExpat Member

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    Oh, all of my gas blocks are aligned with great care. Knowing the gas port diameter when I was putting these together would have told me nothing as I was unaware that a reputable barrel mfr would make the port too large.

    One thing that I have often wondered ...

    Why don't GB mfrs lightly scribe center-line marks on the rear of the GBs that could easily be lined-up on a like center-mark provided by barrel makers on their products. I think that it would make the whole "carefully lining up the gas block" process MUCH easier ... y'know? :)
     
  10. LoonWulf

    LoonWulf Member

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    Again not giving you static, but knowing the port dia would have told you that they would be over gassed, or at least LIKELY to be over gassed.
     
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  11. LoonWulf

    LoonWulf Member

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    I never thought about that........probably make life too easy for us LOL!
     
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  12. GBExpat

    GBExpat Member

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    <chuckle> Well, DUH! :)

    OT, sorta ...

    That brings to mind the time that I built what I think of as my "carbine" FAL. Must have been about 15 years ago.

    Since I cut several inches off of that barrel, I knew that I would have to open up that port for proper function.

    I scoured the forums for expert port-size info. Somewhere I found a plausible report that it shouldn't be opened up more than sizeX but I realized the this fellow could not tell me a MAX for my rifle ... so the long cycle of disassemble/drill/reassemble and test, repeat ... began. It took a-while. WHEW! ... but Easy Does It finally paid off. IIRC, I ended up having to open that pup up to, like, sizeX+15% before the rifle performed reliably. It is one fine little rifle. The favorite of my FALs.

    So I had to wander over to Fotki to see if I had a pic stored:

    2v2u13H6WxAW38L.jpg

    :D
     
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  13. LoonWulf

    LoonWulf Member

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    That's a cool FAL!
     
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  14. js8588

    js8588 Member

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    Faxon is a company I REALLY want to like, but I have yet to see any of their barrels give exemplary accuracy (regularly turn in sub MOA groups). Sure, they will sometimes do it, but I don't see it often around the web.
     
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  15. MistWolf

    MistWolf Member

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  16. tarosean

    tarosean Member

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    whats the allure? are they cheaper than known quality makers?
     
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  17. GBExpat

    GBExpat Member

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    Thanks, MistWolf, but I will be happy with what I consider "decent" accuracy; ~MOA.

    I already have a pair of adjustable Wojteks inbound. I think that there is a very good chance that each of them, after initial setup & optimization, will never be adjusted again. ;)

    If I had rifle(s) on which I was planning to tweak the gas often, I would probably buy one of the Superlatives. For a gas block with port-size options, the BRTs look look very nice. Thanks for the link ... I have added it to my Bookmarks.

    I quickly perused the BRT page and it looks to me like one of those gas blocks along with a set of different-size port plugs (assuming that they have designed them to be user-changeable) would be a very nice way to go on a rifle that you probably won't often change but want to be prepared for feeding changes, periodically, down the road.

    If your gas block is forward of the FFHandguard, it seems to me that it would be easy to pop off the GB, change the port plug and reinstall. You'd probably want to fit the GB a couple of mm forward of the ridge behind the journal so the you could more easily POP the GB loose from the accumulated carbon. Just thinking aloud ... :)
     
    Last edited: Jul 14, 2018 at 9:21 AM
  18. imashooter

    imashooter Member

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    Sorry to hear about your dilemma and I'm sure Faxon will see this through. I have a 16" (mid-length 5.56 - .081") in a side charger that works just fine and is plenty accurate enough. Next week I hope to test my Faxon 10.5" (carbine-length / .080"-.o81") in a pistol build. Both are without an adjustable gas block. Keep us posted.

    Here's a "live" gas port data base for gas port sizes. Obviously based on the honor-system allowing folks to enter factory specs, self-measured diameters, etc. I have entered 2, one being a factory spec and the other I measured which was confirmed with factory data.

    https://docs.google.com/spreadsheet...NxDUlWNK9nEv-cZEQoLq2JXXrk/edit#gid=766121382

    This is the link for you to enter your data: https://docs.google.com/forms/d/e/1FAIpQLSdeViTKwQRFjSMRxlBGZ4opFoLDv3putmin_a_nYDiAJWx-xg/viewform
     
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  19. MistWolf

    MistWolf Member

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    Imashooter, I can tell you from personal experience, an .081" gas port in a 10.5" barrel is far too large.
     
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  20. js8588

    js8588 Member

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    No, they aren't. What they are is somewhat more innovative. They offer profiles & cartridge options that many other companies do not.

    Honestly, I've read more sub MOA reports from Bear Creek Arsenal barrels than I have from Faxon.
     
    Last edited: Jul 14, 2018 at 11:58 AM
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  21. imashooter

    imashooter Member

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  22. imashooter

    imashooter Member

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    Reckon we'll find out.

    Green Mountain shows as .087 (carbine)

    Mega Arms = .080 (carbine)

    LMT = .084 - .086" (carbine)

    Anderson = .086" (carbine)

    Others in mid-high .07s

    I understand most over-gas to satisfy the masses (one size fits all) but I doubt if it meets the threshold of "far too large".

    Thanks
     
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  23. shootstraight57

    shootstraight57 Member

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    I agree with js58588. I have 2 Bear Creek Arsenal barrels and both shoot sub MOA. One I ordered a completed upper and the second I ordered only the barrel.
     
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  24. MarshallDodge

    MarshallDodge Member

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    GBexpat-

    What buffer are you using? You do realize that the buffer weight will contribute to early unlocking?

    I have an 18" rifle length gas Faxon gunner barrel that is fantastic. It shoots way better than expected, and I have shoot it out to 800 yards on a reduced steel silhouette using 77 Noslers.
     
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  25. imashooter

    imashooter Member

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    Regarding Faxon accuracy, I have only fired my 16". I can easily do 1/2" groups at 50 meters with a red dot (2 moa). Very easily. More than good enough for me. Hope to do the 10.5" nlt Thursday this coming week.
     
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