AR308 cycling problems... is this over or under gassed?

[cunnerman]

No kidding. I even went with their bcg to help try to avoid any issues and look where we are at. Does your long tube allow the bolt to go all the way into battery?

Yes, bolt seats fully. But it's clearly getting way too much gas due to the extended gas-tube length and resulting added dwell time.

What's crazy is I can find posts years old on other forums with people beating their heads against the wall with the exact same problem with Wilson Combat Super Sniper barrels. How have they not corrected this yet?!?!?

 

[thehun]

My Criterion M118LR barrel has been amazing. It is such an awesome barrel.

I have the rareish 22” rifle gas with the hybrid profile … starts out at 1.2” and tapers to .800” … nitride, 1:11 twist.

This is what XM80c shot out of it … 5-shot group … cold bore … SLR gas block with a YHM R2:

 

[tylerradke]

Yes, bolt seats fully. But it's clearly getting way too much gas due to the extended gas-tube length and resulting added dwell time.

What's crazy is I can find posts years old on other forums with people beating their heads against the wall with the exact same problem with Wilson Combat Super Sniper barrels. How have they not corrected this yet?!?!?

I don't know. I haven't spent much time with mine yet, but when I saw your post I was kinda shocked to see the same parts and same issues. I always heard wilson barrels were pretty good so didn't think that was the issue. I still feel mine is undergassed because I have turned mine down and had worse results. I'm curious about the longer gas tube though now. I need to get mine out soon and try to figure it out. I guess I could turn my gas off and start going a couple clicks at a time just to make sure it's not super overpasses, but I really don't think that's the issue. I wonder which gas tune wilson uses in their factory built rifles.

 

[cunnerman]

I wonder which gas tune wilson uses in their factory built rifles.

I'd really love to know.

Based on my measurements I need a 15.375" gas tube for the end to land at the correct point on the cam-pin cutout. And a 15.375" that's just not a thing that anyone makes.

Based on some other threads I've stumbled upon, some folks with similar issues seem to have had some success taming the WC SS gas kick with a Tubbs 308 Flatwire. I have one sitting here, and will just throw it in my test bin for my next range trip.

 

[mettee]

What kind of barrel profile do you want?

The criterion is a solid option, Rainer has a nice stainless one that's heavier, there is also jp, etc. Tough to hit sub $500

 

[cunnerman]

What kind of barrel profile do you want?

I honestly don't know... right now I'm just frustrated, pissed, and venting at WC's stupidity.

Twist my arm... what do you suggest?

 

[thehun]

I'd really love to know.

Based on my measurements I need a 15.375" gas tube for the end to land at the correct point on the cam-pin cutout. And a 15.375" that's just not a thing that anyone makes.

Based on some other threads I've stumbled upon, some folks with similar issues seem to have had some success taming the WC SS gas kick with a Tubbs 308 Flatwire. I have one sitting here, and will just throw it in my test bin for my next range trip.

They use Armalite length.

 

[mettee]

I honestly don't know... right now I'm just frustrated, pissed, and venting at WC's stupidity.

Twist my arm... what do you suggest?

Not sure, but you are gonna chase this all over the place and it's gonna just get more frustrating I think unless you change it out, sadly.

Criterion is good, but I don't think they have many options in stock. Going custom is good, but will be over 500. Xcaliber? I think they make more affordable custom barrels but I don't know their reputation. Craddock, good choice but again over 500. McGowen, but they all have long wait times.

 

[hkguns]

This isn't as hard as you're making it out to be, nor is it a WC engineering problem, its a builder problem.

From the 308 20" Super Sniper page on the WC site. They literally TELL you what to buy that will work.

• Chamber: .308 Winchester
• Feed Ramps: M4 style
• Finish: Matte bead blasted stainless
• Gas Block Seat: .875" x .920" - Dimpled for set screw
• Gas System: Rifle length
• Length: 20"
• Material: Stainless steel - Type 416R
• Muzzle Threads: 5/8" x 24
• Profile: Super Sniper (Fluted)
• Rifling: 1:10 - Button rifled
• Weight: 50.7 oz.
• Matching Gas Block: #TR-LPGB-M
• Matching Gas Tube: #TR-GTR-10

AR10's aren't AR15's, source your components accordingly and wisely.

 

[cunnerman]

This isn't as hard as you're making it out to be, nor is it a WC engineering problem, its a builder problem.

From the 308 20" Super Sniper page on the WC site. They literally TELL you what to buy that will work.

• Chamber: .308 Winchester
• Feed Ramps: M4 style
• Finish: Matte bead blasted stainless
• Gas Block Seat: .875" x .920" - Dimpled for set screw
• Gas System: Rifle length
• Length: 20"
• Material: Stainless steel - Type 416R
• Muzzle Threads: 5/8" x 24
• Profile: Super Sniper (Fluted)
• Rifling: 1:10 - Button rifled
• Weight: 50.7 oz.
• Matching Gas Block: #TR-LPGB-M
• Matching Gas Tube: #TR-GTR-10

AR10's aren't AR15's, source your components accordingly and wisely.

Thanks for your help... Operator error it seems!

I have the TR-GTR-10 tube, and will order their suggested gas block and give it the old college try.

 

[mettee]

I found a pic of that gas block and you can see that the set screw location is shifted.

 

[cunnerman]

I found a pic of that gas block and you can see that the set screw location is shifted.

I assume you mean roll pin?

The roll pin location is noticeably farther forward on the WC gas block compared to the SA block. This looks to be the exact difference in distance I'm trying to correct.

I'm going to call them first thing tomorrow morning to see if their AGB will mate correctly as well.

 

[bfoosh006]

Sorry If I missed it, but did you happen to try some 150'ish gr ball ammo ?

I can't help but wonder if the ammo tried, the Terminal Ascent or the FGMM TMK "might" be seated into the lands of the barrel.
Try the black sharpy coated bullet test.

Also, you posted a pic of a bashed fired case mouth that is dented... that is very, very possibly from ejection... it is hitting the side lug at the ejection port side, fairly common BTW.

Also, I would suggest giving the chamber a GREAT cleaning... Wilson barrels tend to have tight chambers.

And have you tried the , One round, mag loaded fed and fired, to see if the BCG will consistently lock back 100% ?

And did you happen to get pics of your fired brass at the headstamp ? May as well post pics of the whole fired case.

Myself, I am also not convinced your gas port is to small, or your gas tube length is an issue.
Gas tube wise, DPMS pattern gas tubes extend even less into the cam cutout. Much less, compared to a Armalite gas tube, and all my DPMS pattern gas tube function just fine.

I guess I am saying, if your gas port / gas tube was to small / "short"... you wouldn't be getting beat up upon firing.

I would try adjusting your Adj. GB again, from the being of the instructions.... after the one round mag fed and fired , BCG locks back test.

Leave the gas port size as is... buffer setup seems just fine, let us know if the single round / BCG lock back works consistently.

And... how many total rounds fired through the rifle ? Guesstimation is fine

 

[hkguns]

I assume you mean roll pin?

The roll pin location is noticeably farther forward on the WC gas block compared to the SA block. This looks to be the exact difference in distance I'm trying to correct.

View attachment 8284356

I'm going to call them first thing tomorrow morning to see if their AGB will mate correctly as well.

I think you are on a solid path now.

 

[cunnerman]

I think you are on a solid path now.

Thank you for your help!!!

If this works out, I'll owe you a beer... or six!

 

[bfoosh006]

And FWIW, this thread shows how far apart a DPMS pattern gas tube v. a Armalite Pattern gas tube are...

https://www.snipershide.com/shootin...arrel-to-determine-gas-system-length.7171789/

See the pics rpoL98 posted... BOTH patterns work, given the correct use in the right "pattern"... so don't worry about the actual entire context of that thread. ( IE, the short DPMS gas tube WILL cause function issues in a Armalite )

 

[mettee]

I assume you mean roll pin?

The roll pin location is noticeably farther forward on the WC gas block compared to the SA block. This looks to be the exact difference in distance I'm trying to correct.

View attachment 8284356

I'm going to call them first thing tomorrow morning to see if their AGB will mate correctly as well.

Both actually, the roll pin is, and the set screw location looked like it was biased to one end. I do think this will correct your gas tube location.

Might just be the wrong pic but here:

 

[msgriff]

I assume you mean roll pin?

The roll pin location is noticeably farther forward on the WC gas block compared to the SA block. This looks to be the exact difference in distance I'm trying to correct.

View attachment 8284356

I'm going to call them first thing tomorrow morning to see if their AGB will mate correctly as well.

The Wilson gas block shown and listed previously (TR-LPGB-M) is their standard low profile gas block suitable for any AR-15 or AR-10/308 with a 0.875" journal. The roll pin location, measured from the front, is different because the length of the gas block body is shorter than most (0.920"). The bore for the gas tube is drilled through, so you will see the end of the gas tube at the front. Most gas blocks are longer (~1") and the bore for the gas tube is not drilled completely through. Set screw spacing is 0.400", which is closer than most other blocks, but not unheard of.
I believe that Wilson, and one or two others, intentionally placed their gas port location as they do from early on. The intent was to use standard AR-15 gas tubes and to disengage from the gas key shortly after the bolt unlocked, as you mentioned before. People had issues with this causing short stroking, and would source the ArmaLite length gas tubes from elsewhere, as Wilson did not always spec or even sell the ArmaLite length tubes. There is a risk with using the longer gas tube, as it can bottom out in the gas key. This issue is even referenced in the reviews for the 15.5" gas tube on Wilson's site:
"I installed this on WC 18" 308 Super sniper barrel with rifle length gas system on a aeroprecision upper and jp enterprises BCG. And it was to long for bolt to fully close."

 

[cunnerman]

Both actually, the roll pin is, and the set screw location looked like it was biased to one end. I do think this will correct your gas tube location.

Might just be the wrong pic but here:

It’s this kind of crap that is the problem with the AR308 market… on top of an already confusing non-mil-spec platform, you have outfits like Wilson Combat pumping out proprietary gas systems that won’t function properly if god-forbid you go outside their ecosystem. Honestly, it just makes me not want to buy any WC stuff ever again.

 

[Top O' Texas]

My Criterion M118LR barrel has been amazing. It is such an awesome barrel.

I have the rareish 22” rifle gas with the hybrid profile … starts out at 1.2” and tapers to .800” … nitride, 1:11 twist.

This is what XM80c shot out of it … 5-shot group … cold bore … SLR gas block with a YHM R2:

+1 on those barrels!

 

[thehun]

+1 on those barrels!

Yeah I’ve yet to “waste” my M118LR stash as it shots ball realllly well…

 

[Top O' Texas]

The Wilson gas block shown and listed previously (TR-LPGB-M) is their standard low profile gas block suitable for any AR-15 or AR-10/308 with a 0.875" journal. The roll pin location, measured from the front, is different because the length of the gas block body is shorter than most (0.920"). The bore for the gas tube is drilled through, so you will see the end of the gas tube at the front. Most gas blocks are longer (~1") and the bore for the gas tube is not drilled completely through. Set screw spacing is 0.400", which is closer than most other blocks, but not unheard of.
I believe that Wilson, and one or two others, intentionally placed their gas port location as they do from early on. The intent was to use standard AR-15 gas tubes and to disengage from the gas key shortly after the bolt unlocked, as you mentioned before. People had issues with this causing short stroking, and would source the ArmaLite length gas tubes from elsewhere, as Wilson did not always spec or even sell the ArmaLite length tubes. There is a risk with using the longer gas tube, as it can bottom out in the gas key. This issue is even referenced in the reviews for the 15.5" gas tube on Wilson's site:
"I installed this on WC 18" 308 Super sniper barrel with rifle length gas system on a aeroprecision upper and jp enterprises BCG. And it was to long for bolt to fully close."

Is that overall length or rifle gas length? I don't have my cheat sheet with me right now, but I do have all non-armalite tube lengths along with concuring gas lengths.

 

[Top O' Texas]

Yeah I’ve yet to “waste” my M118LR stash as it shots ball realllly well…

Although I don't have any m118 ammo, it does shoot m80 (pmc bronze) well.

 

[Redlion]

OP it sounds like trying out the WC gas block could be a solution. I used most of the same components on my AR.308, other than using an adjustable JP gas block and a Rainier Ultra Match 20" barrel. If you end up wanting to try a different barrel, the Rainier Ultra Match has performed very well for me.

 

[Top O' Texas]

Back to the tube length statements. If the tube is too long it shouldn't fully lock (bcg) and wouldn't be able to fully know if go/no-go is correct. Since you stated the no-go didn't lock then the tube should be the correct length. If the gas port is to small a heavier spring and/or buffer won't help. Has it ever run correctly?

 

[Top O' Texas]

I MIGHT have found an answer! Just reread the OP and noticed you're using a superlative gas block. I've had 3 bad blocks from them (all were adjustable).

 

[thehun]

I do also agree that using the WC gas block will fix the OPs problems …

 

[cunnerman]

Just got off the phone with Wilson Combat and it was... interesting.

First, the guy I spoke with (who sounded like he was 16) wasn't 100% sure their AGB would work on their 20" 308 Super Sniper barrel but, "thinks it will." Not terribly confidence inspiring.

Then, when I asked if I needed the straight or standard gas tube he said, "I'm not sure, I think the standard one should work." WTF. Once again... You think it will work?

I'm ordering the gas block, but I'm done with WC after this. They make proprietary parts and then don't even know if they're compatible with their own stuff... What a complete joke of a company.

 

[mettee]

You plan to shoot suppressed at all?

Only reason I ask is that will render the WC gas block useless. You'll want to be able to adjust gas at the point you go suppressed, ignore if you arent going to.

You have a nice SA gas block.

Nothing wrong with the Wilson barrel or gas block but it's proprietary length. I still lean toward the criterion barrel but....gotta leave it up to you there. Ignore if you aren't going suppressed.

 

[Top O' Texas]

When I'm on WC's site there isn't enough info on journal size let alone port size and gas length (proprietary or not). At least have a cheat sheet for those not knowing easy answers!

 

[thehun]

Just got off the phone with Wilson Combat and it was... interesting.

First, the guy I spoke with (who sounded like he was 16) wasn't 100% sure their AGB would work on their 20" 308 Super Sniper barrel but, "thinks it will." Not terribly confidence inspiring.

Then, when I asked if I needed the straight or standard gas tube he said, "I'm not sure, I think the standard one should work." WTF. Once again... You think it will work?

I'm ordering the gas block, but I'm done with WC after this. They make proprietary parts and then don't even know if they're compatible with their own stuff... What a complete joke of a company.

I bet he was a qualified hire …

 

[cunnerman]

You plan to shoot suppressed at all?

Yes. Which is why I need an adjustable option. Otherwise I'd just buy their fixed block. Frustrating they don't have more info.

When I'm on WC's site there isn't enough info on journal size let alone port size and gas length (proprietary or not). At least have a cheat sheet for those not knowing easy answers!

Loool... I love how they link to this "detailed schematic," which literally just says "Rifle Length Gas System" with no measurement whatsoever. I'm guessing they don't publish it because they use a proprietary non-standard distance for their gas port placement. What a shit show.

 

[thehun]

Well. You can always get a RCA adjustable gas key … works great on my AR15 …

I don’t think you’ll have an adjustable gas block with that WC barrel …

 

[Top O' Texas]

Well. You can always get a RCA adjustable gas key … works great on my AR15 …

I don’t think you’ll have an adjustable gas block with that WC barrel …

I have a few rca adjustable gas keys and adjustable bc's. No issue so far.

 

[Top O' Texas]

Yes. Which is why I need an adjustable option. Otherwise I'd just buy their fixed block. Frustrating they don't have more info.



Loool... I love how they link to this "detailed schematic," which literally just says "Rifle Length Gas System" with no measurement whatsoever. I'm guessing they don't publish it because they use a proprietary non-standard distance for their gas port placement. What a shit show.

Kinda stupid in a way, because all someone would need to do is buy the parts and measure from there.

 

[tylerradke]

I MIGHT have found an answer! Just reread the OP and noticed you're using a superlative gas block. I've had 3 bad blocks from them (all were adjustable).

What was wrong with your superlative gas blocks?

 

[Top O' Texas]

What was wrong with your superlative gas blocks?

Wouldn't adjust at all. Almost like it was getting bypassed?

 

[Ernest 5.56]

Just got off the phone with Wilson Combat and it was... interesting.

First, the guy I spoke with (who sounded like he was 16) wasn't 100% sure their AGB would work on their 20" 308 Super Sniper barrel but, "thinks it will." Not terribly confidence inspiring.

Then, when I asked if I needed the straight or standard gas tube he said, "I'm not sure, I think the standard one should work." WTF. Once again... You think it will work?

I'm ordering the gas block, but I'm done with WC after this. They make proprietary parts and then don't even know if they're compatible with their own stuff... What a complete joke of a company.

BARREL, .308 WINCHESTER, SUPER SNIPER, 20", FLUTED, STAINLESS, GLASS BEAD, 1-10

Experience the precision of Wilson Combat's Super Sniper stainless barrel. This 20" barrel is designed for the .308 Winchester, providing shooters with an exceptional option when accurate long range results are required or demanded.

wilsoncombat.com

I see this and a schematic listed under product details. I think they've slightly changed the part numbers and forgot to update this listing

Matching Gas Block: #TR-LPGB-M
Matching Gas Tube: #TR-GTR-10

 

[mettee]

What was wrong with your superlative gas blocks?

Wouldn't adjust at all. Almost like it was getting bypassed?

I think the general concensus was that the key was staying engaged with the gas tube too long, putting it well outside the adjustment range where normally the key would have typically completely disengaged the tube, his was not.

I say keep the SA block and ditch proprietary stuff. But it's not my money

 

[ironman56]

I just built a AR10 using almost the same components, mine functions fine although the recoil does seem a little extreme, but I don't have another 308 semi to compare it to . When I was researching my build I remember reading that the Wilson supersniper used a longer gas tube than a normal rifle length tube , but they were out of stock , but read somewhere that Fulton armory AR10 tube were the same , so that's what I got and it works , I used a A2 style magpul moe stock and Areo receiver tube and spring and buffer assembly. So that might make a difference, took mine to the range for the 2nd time today , not all that impressed so far ,maybe it needs more break in. Using 168 FGMM.only 1-1/4 @ 100 yds, but did ring steel at 500 so not terrible.

 

[cunnerman]

I just built a AR10 using almost the same components, mine functions fine although the recoil does seem a little extreme, but I don't have another 308 semi to compare it to . When I was researching my build I remember reading that the Wilson supersniper used a longer gas tube than a normal rifle length tube , but they were out of stock , but read somewhere that Fulton armory AR10 tube were the same , so that's what I got and it works , I used a A2 style magpul moe stock and Areo receiver tube and spring and buffer assembly. So that might make a difference, took mine to the range for the 2nd time today , not all that impressed so far ,maybe it needs more break in. Using 168 FGMM.only 1-1/4 @ 100 yds, but did ring steel at 500 so not terrible.

What gas block?

 

[ironman56]

What gas block?

I used the standard WC gasblock that was recommended on the website with the barrel, non adjustable.

 

[ironman56]

I used the standard WC gasblock that was recommended on the website with the barrel, non adjustable.

I'm curious if maybe you've got the wrong gas tube , WC supposedly drills their gasport farther down the barrel than most manufacturers, and you need a longer gastube , there's a thread here somewhere about it .

 

[Top O' Texas]

If you need to measure, measure from the closest screw (if it has screws) under the gb to the receiver. DPMS standard rifle gas will be 12.7" to the front of the receiver. I'd forgo the end of the tape and start at 1" measuring as not to deal with the metal piece that moves on the tape.

 

[cunnerman]

I'm curious if maybe you've got the wrong gas tube , WC supposedly drills their gasport farther down the barrel than most manufacturers, and you need a longer gastube , there's a thread here somewhere about it .

It’s been discussed in this thread…

WC drills their gas port at a proprietary distance… splitting the difference between AR10 length and LR308 length. It’s borderline retarded and makes it impossible to use anything other than WC products.

Using “standard” gas blocks requires a custom gas tube of the appropriate length (which I think is 15 and 3/8”). Conversely, using standard gas tubes requires a WC gas block. Because they have the roll pin shifted to accommodate their dumb design.

 

[ironman56]

It’s been discussed in this thread…

WC drills their gas port at a proprietary distance… splitting the difference between AR10 length and LR308 length. It’s borderline retarded and makes it impossible to use anything other than WC products.

Using “standard” gas blocks requires a custom gas tube of the appropriate length (which I think is 15 and 3/8”). Conversely, using standard gas tubes requires a WC gas block. Because they have the roll pin shifted to accommodate their dumb design.

Guess I missed that , now I wonder if I've got the wrong gas tube , WC was out of stock when I bought my barrel and I got mine from Fulton, my gun runs fine , but the recoil seems a little harsh, I'll order one of WC's tube when they're in stock just in case , cheap enough. I retorqued my barrel nut today to 58 ft# and cleaned the barrel real good , hopefully that will get my groups down to sub moa.

 

[Top O' Texas]

It’s been discussed in this thread…

WC drills their gas port at a proprietary distance… splitting the difference between AR10 length and LR308 length. It’s borderline retarded and makes it impossible to use anything other than WC products.

Using “standard” gas blocks requires a custom gas tube of the appropriate length (which I think is 15 and 3/8”). Conversely, using standard gas tubes requires a WC gas block. Because they have the roll pin shifted to accommodate their dumb design.

Is that gas length or overall length? 14.625" is roughly overall length on dpms rifle gas tube and 12.7" from front of receiver to port.

 

[msgriff]

OP, if you think that your issues will be solved with a custom length gas tube, they are available for around $35 in any length you want.

 

[Top O' Texas]

OP, if you think that your issues will be solved with a custom length gas tube, they are available for around $35 in any length you want.

White Oak will cut him 1 for I think that amount? Just need to let them know exact length is all.

 

[cunnerman]

OP, if you think that your issues will be solved with a custom length gas tube, they are available for around $35 in any length you want.

I found those guys. Just haven’t disassembled my rig yet to do exact measurements. May do that tomorrow just for my own edification and to add to the information in this thread for future readers.

It’s also probably the simplest and most permanent fix.