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AR308 cycling problems... is this over or under gassed?
- Thread starter cunnerman
- Start date
I might get some parts from them as long as it WILL NEVER BE a barrel! That causes gb and tube priority issues! Me not like those "P" words..........I'll stop and say no more about that letter 
Ok... I took the barrel out of my build and came up with a measurement of right around 13.75"+ a hair for the gas port distance.
Working off the White Oak Armament custom gas tube diagram, I should add 1.610" to that measurement, which works out to 15.375" almost exactly. Doing the math in reverse, 15.375" minus 1.610" gives me 13.765" which I'm guessing is exactly what I have.
I'm going to go ahead and order a custom length 15-3/8" gas tube, but I'm going to call White Oak first and see if this is something they've run into in the past with GWC. That is, Goofy Wilson Combat.
Pics below...
Working off the White Oak Armament custom gas tube diagram, I should add 1.610" to that measurement, which works out to 15.375" almost exactly. Doing the math in reverse, 15.375" minus 1.610" gives me 13.765" which I'm guessing is exactly what I have.
I'm going to go ahead and order a custom length 15-3/8" gas tube, but I'm going to call White Oak first and see if this is something they've run into in the past with GWC. That is, Goofy Wilson Combat.
Pics below...
I'm not sure that follows either... the AR10 rifle length tube is only 1/8" too long. Not 1-1/8" too long.
The schematic says rifle length but no measurements. Lol It might be worth calling Wilson again and just speaking to someone else to get the gas tube
part was #TR-GTR-10
I think the number has changed slightly since they redesigned the website
part was #TR-GTR-10
I think the number has changed slightly since they redesigned the website
Attachments
I had the TR-GTR-10, which is what's causing the overgassing problem due to the tube being too long creating too much gas key dwell.
I found this discussion on Reddit late last night with an almost identical build as mine (WC SS 308 20" barrel, SA agb, Aero M5 upper)... gonna drop in the standard rifle length 15.125" tube and see what happens.
His pictures shows what is traditionally considered "too short" of a position for the tube-end in the cam-pin cutout, but if it worked for him I have to give it a try.
My bad maybe I missed it but are you using the fixed wilson gb currently or the superlative ?
That was a measurement from front of receiver to port, not total length I stated. If the tube is to long then it shouldn't go into battery all the way. The longer than normal tube will keep it from locking into the extension. When and if the hammer could hit the pin the amount of blowback would cause the buffer tube to blow up from the buffer being forced out the back.
I can understand the frustration, however, I'm not so sure all the WC vitriol is completely warranted. Especially when we all know there is no real AR10 standard that everyone follows. It is up to us to make the right component choices.
I had no issue getting my WC AR10 or other WC barrels to go together properly. However, on the AR10, I tried to use components from one source because I knew there could be issues and didn't want to deal with the frustration the OP is presently enduring. Plus I checked everything 5 times before ordering.
That barrel is a good barrel, I wouldn't be so quick to dump it. I have a couple of them and they shoot great with just a smidge of a tight chamber.
KAC and even the G-man make barrels with other than standard C - M - R length gas port locations for the AR15 platform.
.......and no, I don't work for WC.
I had no issue getting my WC AR10 or other WC barrels to go together properly. However, on the AR10, I tried to use components from one source because I knew there could be issues and didn't want to deal with the frustration the OP is presently enduring. Plus I checked everything 5 times before ordering.
That barrel is a good barrel, I wouldn't be so quick to dump it. I have a couple of them and they shoot great with just a smidge of a tight chamber.
KAC and even the G-man make barrels with other than standard C - M - R length gas port locations for the AR15 platform.
.......and no, I don't work for WC.
Gonna disagree somewhat... WC mixing in a new/proprietary dimension in an already confusing market segment is pretty stupid. Wouldn't it make more sense to maximize compatibility with the most "standardized" parts? But whatever, WC gon do what WC gon do.
Also... how can it be "up to us to make the right component choices" when WC doesn't even have an accurate schematic/dimensioning of their barrel on their website? It's rather annoying on their part.
All that being said, I am going to stick with the barrel. I just swapped in the standard 15.125" rifle length tube based on this guy's success with the same SA agb, barrel, and M5 upper. White Oak also recommended doing the same before I go ordering something custom.
>>>> FWIW, the customer service rep I spoke with at White Oak said "Wilson Combat is an oddball for sure." Makes me feel better knowing I'm not alone in my opinion of them.
Anyway, I'm going to try to get out to the range and test it today or tomorrow. I'm failry confident it will all work now, despite the tube being "too short" by most accepted standards.
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Is the 15.125" overall or to the port? I measured a dpms rifle length tube and it measures overall at your stated length. Length to the port is 14.5625" (14 9/16").
- Overall length to port is 13.75" plus-a-hair. Less than half 1/16". I'm calling it 13.76"overall length to the port.
- The 15.5" is the overall length of the WC "AR10 rifle length gas tube" which placed the tube in the back half of the cam-pin cutout and caused severe overgassing.
- The 15.125" is the overall length of a standard rifle length tube. It will look "too short" in the cam-pin cutout, but appears to be an option that has worked with this WC 20" SS barrel and SA agb.
With no standard in AR10 unlike 15's is a pita. Having gen2 dpms, gen1 dpms, sfar and armalite just to deal with is enough and now micro lengths of a 1/16 or 3/8 on getting the correct tube length is ridiculous. Does jp also use a special tube pin size? Hopefully all goes well and update as needed.
Wow! Over the last year, I have magically built almost the same setup. I went with an AP tube (15.125") and AGB instead. Have not fired it yet because I've been saving for some glass to finish the build. I may have to rob Peter to pay Paul so I can verify operation and share my findings. Hunting season is over and my hunting rifle doesn't need it's scope right now anyway.
I think the 15.125" tube is the way to go with (most) non-WC AGBs and WC barrel.
I'm still hoping to get out this week to test...
Tested the 15.125” gas tube today, and now she’s definitely undergassed. The casing gets ejected but a new round isn’t stripped off by the bolt… and in slow-mo I can see the bolt isn’t going all the way back.
Seems like it’s still a bit shy of cycling reliably, so I’m going to bite the bullet and buy the 15.375” custom gas tube from White Oak, because I want to keep the SA agb and also run my suppressor.
For those who have been following this thread, the severe recoil is gone, which makes me think my initial overgassed assessment was correct on the 15.5” tube.
I will follow up in a few weeks once the custom 15.375” tube comes in!
Seems like it’s still a bit shy of cycling reliably, so I’m going to bite the bullet and buy the 15.375” custom gas tube from White Oak, because I want to keep the SA agb and also run my suppressor.
For those who have been following this thread, the severe recoil is gone, which makes me think my initial overgassed assessment was correct on the 15.5” tube.
I will follow up in a few weeks once the custom 15.375” tube comes in!
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Definitely looks to be way undergassed based on the ejection position in the last image. Are you shooting with the SupArms AGB wide open or at the default 18 clicks?
I would be curious to see if you were to close the AGB down to 18 clicks, where the brass ejection position would be...
Well...how about that. My dyslexic brain went the opposite damn direction (lol). I mean to say 22 clicks...
Main point was to adjust the gas block a small amount and see what position the brass is ejecting. Then go from there. (maybe I haven't sufficiently caffeinated myself today. ROTF)
Heck, I am not even SURE that I am awake...I think you were just checking if people were awake
Not the agb... this thread is a never-ending saga and rabbit-hole chronicling of Wilson Combat retardation. Not gonna rehash everything here on page 3.
Stupid long story short... I need a custom-length gas tube because I'm mixing standard parts (SA agb) with Wilson Combat proprietary stupidity.
Yeah, I have (attempted) to follow the thread; weak attempt to assist and solving the undergas situation as much as you can, given the circumstances.
Question? So here I go at an attempt to try and understand what WC does? How far from the front of the receiver is the gas port? All dpms style/compatible bcg's are the same to the gas key, so no need measuring. If you could start at 1 or the 2" mark and measure from there, then subtract the 1 or 2". This gas length unknown is crazy. You state SA block, but to the or from the tube pin hole is it different than the WC block? I guess it would be the same if the gas tube isn't made differently? In general the end (gas tube toward the muzzle end) is .625" (5/8"). To the roll pin hole to the port is .4375" (7/16"). Overall rifle length tube 15.125" with gas system reference being 12.875" (12 7/8" roughly).
I think the custom gas tube will solve the issues, that was the simplest cheapest solution. Hope to see you shooting without issue soon.
I’ll try and quickly summarize, although I don’t have port distance from receiver (I’ll get that upon next, and hopefully final, teardown - when I install the custom tube).
Port distance from breech (end of barrel) is 13.75 plus a hair. Just guess-timating to make the math work out, I’m using a-quarter-of 1/16th inch for the “hair,” which equals .015625. See image below.
Using the White Oak guideline of adding 1.61” to the overall gas port distance we get:
13.75 + .015625 + 1.61 = 15-3/8” almost exactly
Since 15.125 is way too short, and 15.5 is way too long, I’m hoping this is the answer I’m looking for.
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Just ordered the custom gas tube from White Oak.
After a lot of measuring, remeasuring, and consternation, I ultimately went with a 15.3" tube, which sort of splits the difference between the 15.5" and the 15.125".
They estimate 1-2wk ship times right now. I'll follow-up once it's installed and tested.
After a lot of measuring, remeasuring, and consternation, I ultimately went with a 15.3" tube, which sort of splits the difference between the 15.5" and the 15.125".
They estimate 1-2wk ship times right now. I'll follow-up once it's installed and tested.
Found yet more bitching about Wilson Combat's gas port positioning on AR308.com. This guy went through the exact same bullshit I am.
Sounds like they're the retard players in the 308 game... man, these guys really need to get their shit together.
Sounds like they're the retard players in the 308 game... man, these guys really need to get their shit together.
Well that was fast! Just got the shipping notice from White Oak Armament... the custom gas tube might be here as soon as this weekend!
After more reading and more measuring, I wasn't sure if 15.3125" or 15.375" was the correct length, so I split the difference and went with 15.35". Hopefully I can test as soon as Saturday.
After more reading and more measuring, I wasn't sure if 15.3125" or 15.375" was the correct length, so I split the difference and went with 15.35". Hopefully I can test as soon as Saturday.
Anxiously waiting to hear how this works for you. I should get time next week to shoot mine with the short tube still. Gonna throw my sandman on it and see if it will run with it. Question for you. With the short tube was your brass still getting beat up?
Brass was not beat up with the short tube, but she was still a long way from proper cycling.
I am so confused by mine. It says undergassed with cycling issues but then the recoil and demolished brass leads me to being overpasses. I have turned my gas block down and it cycles worse. Hoping my suppressor will help me figure it out without making it even more complicated. Small frames are so much easier to troubleshoot it seems.
You just have to match parts properly … my AR10 setup was dialed in with less than 10 rounds of ammo.
Do you have a Wilson Combat barrel and a non-Wilson Combat gas block? This kind of setup is a source of major problems due to their screwball gas port placement.
My ejection pattern indicated undergassed at first, but the fierce recoil was clearly demonstrative of an overgassed system. Post pics of inside your upper, showing the end of the gas tube.
Also, what gas block, BCG, and buffer system are you using?
Wilson barrel and bcg, rifle buffer system, and superlative gas block and ar15 rifle tube. It is short in the upper. I have messed with the gas block to try to rule out overgassed and it cycles even less reliably when I turn it down. But it beats the hell out of the brass and recoil is more than I feel it should be. Fgmm will not lock bolt back on empty mag or chamber new round. LC m118 old stuff from the 80s runs about 90%
You're undergassed. You have two options... get a Wilson Combat gas block, or, if you want to stick with the Superlative Arms agb (which I recommend) you'll need a custom 15.375" gas tube from White Oak Armament.
I'm guessing they keep these in stock. It's a common length for certain configurations, and my order shipped in less than 24-hours. Put that in and set the gas block to five full turns and report back.
I believe this was mentioned earlier...but it seems like there is a mismatch of parts. Obviously, I am outsider looking in....but are you sure the parts are all matching for the platform. Meaning....you're using all DPMS/LR308 and not mixing in Armalite/SR25/AR10 parts?
I am in the process of building one myself...so hoping I have all the parts spec'd matching with the proper platform. Definitely a pain in the ass making heads or tails of the various offerings.
I'm looking forward to hearing your results at the range and the final solution. Thanks for sharing.
I am in the process of building one myself...so hoping I have all the parts spec'd matching with the proper platform. Definitely a pain in the ass making heads or tails of the various offerings.
I'm looking forward to hearing your results at the range and the final solution. Thanks for sharing.
I don't have any WC parts let alone a complete rifle from them. Is WC that bad on compatible parts where WC is extremely proprietary? m110/sr25 is compatible with dpms, but ar10 (armalite) isn't along with fal/rock river parts.
That was why I used a Wilson bcg with a Wilson barrel. Everything else that has to do with the gun actually running should be standard shit. But we are finding out the gas tube is not.
There's really no such thing as "mixing" AR10/LR308 parts when dealing with Wilson Combat... they use a proprietary gas port distance which throws a wrench into the works. It's a massive gray area, which is further complicated by their lack of disclosing these proprietary design decisions on their website or product pages. And there are guys out there who avoid WC entirely because of this issue.
Either stick with 100% WC parts (gas blocks and barrels), or figure out a custom gas-system solution when you step outside of their ecosystem by selecting a third-party gas block.
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I just said screw it and called white oak and told them to send me whatever length you just ordered. Lol I'm over wondering about if I can get it to run with the shorter tube or not. Just gonna put the longer tube in it and go from there.
White Oak gas tube just arrived. Gonna try and drop it in today and test tomorrow.
Photo comparison against Armalite 15.5” tube below.
Here’s hoping third time’s the charm!
Photo comparison against Armalite 15.5” tube below.
Here’s hoping third time’s the charm!
So the new tube is ~1/4" longer than dpms rifle length (15.125")White Oak gas tube just arrived. Gonna try and drop it in today and test tomorrow.
Photo comparison against Armalite 15.5” tube below.
Here’s hoping third time’s the charm!
View attachment 8298044
