Why the infatuation with extended gas for the Valkyrie?

[dang472]

I’ve been battling a gas issue with my 20” +2 Valkyrie barrel and I’m just questioning why there’s a consensus that this cartridge needs extended gas. Glancing at pressures it doesn’t seem all that different than 5.56/6.8/6.5 Grendel.
I’ve got a 20” Wilson Combat barrel on the way with rifle gas to see if my current barrel is the problem. With an adjustable gas block and JP SCS, I cant see why the standard gas system would cause an issue.
Obviously a bunch of guys here are running +2 gas on the Valkyrie, I’m just interested in why that was adopted as the go to right away.

 

[Precision Underground]

What is the gas issue? Gas length is directly related to barrel length. I would guess a 20” would struggle with a +2.

 

[dang472]

Troubleshooting is telling me I’m undergassed. Wide open on the SLR, I’m not reliably locking the bolt back. Factory ammo, book max reloads, doesn’t matter. I’ve swapped lowers, carbine vs rifle buffer tubes. Basically taking parts from working ARs to isolate the issue. Potentially my gas port is undersized or not centered. If the Wilson barrel runs reliably, this barrel is going back to the builder to get checked out.

I was just looking at all of my various ARs with rifle length gas systems in 204, 5.56, 6.8, .308 and just had a random thought as to why the builder of my Valkyrie barrel insisted on the +2 gas.

I know the 6 and 6.5 creedmoor gas guns do well with longer gas (I have 2). Comparing the Valkyrie to the Creedmoors doesn’t make the case that they need the same gas length.

 

[Precision Underground]

No gas is used to move the bolt unless the bullet is between the gas port and the muzzle. How much space is between your gas port and your muzzle? Prob not much with a 20” +2. So yes, if anything is not sized correctly or aligned perfecty you likely won’t have enough gas. Same with 18” ARs with rifle gas. They can work but even with max gas they are starting on the edge of reliability. Have you tried a non adjustable gas block?

 

[BgBmBoo]

Check your gas rings. And if you have a one piece gas ring, replace it with the old three ring style.

I had a recent build give me low gas problems...tried everything before figuring out it was the fancy one piece gas ring not sealing well.
Replaced it with the three ring and then had to adjust the gas block down.

Just something to check.

 

[dang472]

I tried a non adjustable gas block long ago in the troubleshooting process but I can’t remember the other factors I changed along the way. What is funny is Rainier sells an 18” with a +1 gas. What is with this cartridge that a manufacturer went through the trouble of making a special gas tube length? Is the 22 Nosler running into the same issues? Were the early 18” Valkyries ripping bolt heads off while an 18” SPR 5.56 has been running rifle gas for years?

I’ve got the standard 3 ring gas ring and I’ve made sure they’re staggered.

What’s also odd is that I had 2 identical barrels made from the same guy at the same time. I built my AR with the Seekins matched billet receiver set. I built my buddy’s Valkyrie with a standard Aero upper and lower. His ran fine with Federal 90gr and mine is hit or miss on reliability.

Is it possible the 20” +2 gas is right on the edge of undergassed and my tighter receiver is showing it more? The Wilson Combat barrel will tell me more in a few days.

 

[Precision Underground]

I tried a non adjustable gas block long ago in the troubleshooting process but I can’t remember the other factors I changed along the way. What is funny is Rainier sells an 18” with a +1 gas. What is with this cartridge that a manufacturer went through the trouble of making a special gas tube length? Is the 22 Nosler running into the same issues? Were the early 18” Valkyries ripping bolt heads off while an 18” SPR 5.56 has been running rifle gas for years?

I’ve got the standard 3 ring gas ring and I’ve made sure they’re staggered.

What’s also odd is that I had 2 identical barrels made from the same guy at the same time. I built my AR with the Seekins matched billet receiver set. I built my buddy’s Valkyrie with a standard Aero upper and lower. His ran fine with Federal 90gr and mine is hit or miss on reliability.

Is it possible the 20” +2 gas is right on the edge of undergassed and my tighter receiver is showing it more? The Wilson Combat barrel will tell me more in a few days.

I would say more chance that the gas is restricted or being lost somewhere.

 

[RyanScott]

The Valkyrie has a longer dwell time because of lower velocity and 10% more powder than the 223.

 

[Constructor]

A 20 should use a standard rifle length gas for sure and a 24" would run fine with a standard rifle gas. As it is a 24" needs a .098 gas port to cycle with a +2" system and that port is larger than optimum. A hole in the barrel almost half as wide as the bullet...

 

[TonyTheTiger]

Same with 18” ARs with rifle gas. They can work but even with max gas they are starting on the edge of reliability.

Thats been pretty well disproven for several years. Only fudds still agree with it. Mythbusters probably even did a show about it. 18" RLGS is standard procedure these days, even 16" RLGS barrels are easily workable, just too close to the edge for most people.

 

[RyanScott]

I’ve had rifle gas systems in 5.56 down to 17” and it wasn’t an issue. I don’t know what gas system is best for Valkyrie but KAC-mid 16, rifle 18 and +1 20” Don’t worry me in 5.56.

 

[Precision Underground]

Thats been pretty well disproven for several years. Only fudds still agree with it. Mythbusters probably even did a show about it. 18" RLGS is standard procedure these days, even 16" RLGS barrels are easily workable, just too close to the edge for most people.

I have been around 4 18" rifle gas guns in my life and 3 of them needed pampering to work properly. Call me a fudd but I call that going off of the experience I have had. There are tons of threads where people have issues with them. If a hole isn't exactly lined up or a little out of spec or a little dirt or grime gets in the gun you will be the one having issues. Yes some of them work fine but there is pretty much no benefit to stretching your gas system to the edge. Ok it will shoot a little softer but if you grow a set of balls or get an adjustable gas block and/or tune your buffer system you won't need to do that.

 

[TonyTheTiger]

Tons of threads where people have issues? How many of those issues were solved by installing the gas block correctly or being less retarded? There's tons of threads with issues with every conceivable rifle setup, even well known ideal setups. FWIW I've been shooting with guys with over 3 dozen rifle length 18" barrels between them for almost 4 years and all issues have been worn gas rings, loose gas keys or loose gas blocks. With things all buttoned up they've been as reliable as any setup between 20 and 100 degrees, in rain, snow, frost, fine dust blowing everywhere and mud. Maybe outside those limits they suck but most won't ever know.

 

[RyanScott]

I think the reputation for issues comes from non-military ammo of varying pressure. The Mk12 was a fantastically successful weapons system.

 

[Precision Underground]

I think the reputation for issues comes from non-military ammo of varying pressure. The Mk12 was a fantastically successful weapons system.

Yea a high quality gun with QC checks and everything as it should be is fine. But as we know QC and AR are not always married. I think a lot of PSA type companies push the 18" rifle gas to try to be "cool" like the MK12. Then when something is slightly out of spec it becomes an issue.

 

[TonyTheTiger]

I think the reputation for issues comes from non-military ammo of varying pressure. The Mk12 was a fantastically successful weapons system.

I wouldn't even go that far. Countless times I've see guys load hot 77's in a half a mag then 55's at 2500fps in the other half. I do it all the time with a 16" rifle gas system. If you set the rifle up to run the light loads it'll work with anything, albeit you'll be overgassed with the hot stuff.

 

[RyanScott]

My 17 had a .093 port for use with a short two baffle silencer.

 

[Precision Underground]

I wouldn't even go that far. Countless times I've see guys load hot 77's in a half a mag then 55's at 2500fps in the other half. I do it all the time with a 16" rifle gas system. If you set the rifle up to run the light loads it'll work with anything, albeit you'll be overgassed with the hot stuff.

That completely defeats the purpose of having a longer than standard gas system. You talk about it like the whole point is to get a long system just for the sake of trying to make the system work. I’m trying to figure out why you, or guys “all the time” are setting up long gas systems to run 55g slow, light loads and then loading half a mag of hot 77s with them. What’s the point? I am trying to find a logical reason someone would do this “all the time”.

 

[TonyTheTiger]

To win matches.

 

[RyanScott]

Or just shoot all 77s.

 

[Precision Underground]

Or just shoot all 77s.

No no no!

 

[TonyTheTiger]

You guys are more than welcome to shoot a D60 worth off 77 grainers at 5 yard paper just because you have 3 500 yard targets in the middle of a stage. It won't do your split times or your wallet any good though, especially over a two day match.

 

[Precision Underground]

You guys are more than welcome to shoot a D60 worth off 77 grainers at 5 yard paper just because you have 3 500 yard targets in the middle of a stage. It won't do your split times or your wallet any good though, especially over a two day match.

Exactly. 99.9% of people don't do that so your advice on how to set a rifle up is not exactly for the masses. Make sense?

 

[RyanScott]

Your matches have a lot more hosing than the ones I used to shoot.

 

[TonyTheTiger]

Exactly. 99.9% of people don't do that so your advice on how to set a rifle up is not exactly for the masses. Make sense?

I'm not saying everyone should do this. I'm saying plenty of people push the limits of a system and then shoot way more rounds than the average person, those people often share knowledge with others about where exactly the limits are. 18" rifle gas is not the limit. If it was it wouldn't be very easy to run bunny fart loads with.

 

[TonyTheTiger]

Your matches have a lot more hosing than the ones I used to shoot.

It wasn't an exact stage description but it's not unheard of. The rifle stage at the Nordic Tri-Gun this year was pretty close to that though. They built a little shoot house out of plywood and you had to go from shooting point blank to 400 ish yards out of ports several times.

 

[Precision Underground]

I'm not saying everyone should do this. I'm saying plenty of people push the limits of a system and then shoot way more rounds than the average person, those people often share knowledge with others about where exactly the limits are. 18" rifle gas is not the limit.

Right and the first post of mine you disagreed with was me explaining that it is pointless to even get near the limit when there are plenty of other, more reversible ways to slow the BCG down. No need (for 99% of people I guess) to permanently set the whole system up near the limit. It is too easy to end up with one of the tons of problems you read about where someone can't track down why they don't have enough gas. I would much rather easily dial back too much gas rather than spend tons of time troubleshooting why I don't have enough gas while wondering if something is slightly out of spec. It is very simple to take a 16" carbine gas or a 18" mid gas and make it shoot extremely soft. So why deal with a really short dwell if you don't have to?

 

[lash]

I get the feeling that the OP's original question regarding .224V has been lost and the argument going on is about 18" .223s.

So, is it, or is it not necessary to use a +2 (or so) gas system on a longer barreled .224V system?
Talking points:

• 20" barrel (OP) is minimum length for this discussion
• Many are running 22" and 24" barrels on their .224V AR
• The typical velocity of the heavies that the .224V was designed around are about 2600-2800 fps, vs. .223 velocities in the 2800-3100 range
• Probably the most common application for the .224V is heavier barreled, long barreled rifles for varmint hunting or long range shooting
• Many are using light BCGs, but some are using standard weight BCGs

Probably there are some points that I've missed. For my money, I could care less about someone who thinks that they have to be right because they know it all and more about someone who can provide actual experience based facts to support their opinions.

I believe that the OP has a valid question and this will most certainly shake out over time and after enough experienced people have spent time behind this cartridge in this platform. In the meantime, it quite apparent that the discussion could yield some good information for those of us who do not know everything already.

 

[RyanScott]

Could someone with Quickload please calculate port velocities?

 

[Precision Underground]

I get the feeling that the OP's original question regarding .224V has been lost and the argument going on is about 18" .223s.
Probably there are some points that I've missed. For my money, I could care less about someone who thinks that they have to be right because they know it all and more about someone who can provide actual experience based facts to support their opinions.

I believe that the OP has a valid question and this will most certainly shake out over time and after enough experienced people have spent time behind this cartridge in this platform. In the meantime, it quite apparent that the discussion could yield some good information for those of us who do not know everything already.

That was kind of my point. I don't believe it is a Valkyrie specific issue at all and I have experience with the issues short dwell times can present. It goes with the countless other issues people have run into with short dwell times in any caliber. If one thing is not perfect or out of spec or not spec'ed right there will usually be a lack of gas. I do think a +2 on a 22" barrel is warranted but that line of thinking is all based on dwell time, not caliber. I apologize if I am the know it all but the information is relevant to the OPs question.

 

[TonyTheTiger]

It is very simple to take a 16" carbine gas or a 18" mid gas and make it shoot extremely soft. So why deal with a really short dwell if you don't have to?

Extremely soft is apparently very subjective, but we've thoroughly derailed the OP's topic. We can certainly start a new thread to debate it if you'd like.

I get the feeling that the OP's original question regarding .224V has been lost and the argument going on is about 18" .223s.

Your right, I'll be done now.

 

[bigjake83]

Tons of threads where people have issues? How many of those issues were solved by installing the gas block correctly or being less retarded?

LOL...

 

[lash]

No need to apologize. I just wanted the discussion to get back on track because I do not know that much about ARs and am in the learning stages.

I put together a 22" rifle for this cartridge because I wanted something fun to play with at longer distances that would eat reasonable cost off the shelf ammo. I spend enough time loading to feed my match rifles. In my case, I used a standard weight BCG and am having to use every bit of gas I can to make it cycle cleanly and consistently when shooting the 88 Hornady ELDs. The Federal 90 Fusions cycled fine with no adjustments. I am wondering if I would be better off getting a lighter BCG, even though I do have it working well now.

This is my issue and may be related to the OP's question. I don't know. FWIW, mine is a +2 gas tube.

 

[Precision Underground]

No need to apologize. I just wanted the discussion to get back on track because I do not know that much about ARs and am in the learning stages.

I put together a 22" rifle for this cartridge because I wanted something fun to play with at longer distances that would eat reasonable cost off the shelf ammo. I spend enough time loading to feed my match rifles. In my case, I used a standard weight BCG and am having to use every bit of gas I can to make it cycle cleanly and consistently when shooting the 88 Hornady ELDs. The Federal 90 Fusions cycled fine with no adjustments. I am wondering if I would be better off getting a lighter BCG, even though I do have it working well now.

This is my issue and may be related to the OP's question. I don't know. FWIW, mine is a +2 gas tube.

What kind of buffer tube is on it? Carbine or rifle?

And imagine if you had a 20" barrel, issue would be much worse!

 

[lash]

Rifle length buffer tube since it wears a gen 2 PRS stock.

 

[Precision Underground]

Rifle length buffer tube since it wears a gen 2 PRS stock.

If you have an adjustable gas block and are saying you have to open it all the way to get it to cycle reliably I'd say just open it all the way and call it good. If you are worried it is on the edge I would get a lighter buffer rather than messing with the BCG. A lighter BCG is much more expensive and can complicate things even more by removing the mass that is used to move the buffer. You could also try a lighter spring but lighter buffer is prob the easiest.

 

[lash]

If you have an adjustable gas block and are saying you have to open it all the way to get it to cycle reliably I'd say just open it all the way and call it good... .

Yeah that's where I am and I'm not really worried. I take things as they come and deal with them then. Thanks for your input.

 

[dang472]

I appreciate the discussion. I started this build last winter and just accepted the fact that all the big name builders were running + gas because this was some hotrod new cartridge that overwhelmed standard rifle gas. After running real world loads and struggling with gas issues, I started questioning the philosophy.

My 6.8s run great on mid gas, my 308 is on rifle, my 458 socom is mid, my spr 5.56 is rifle etc.

I forgot to mention that I tried a low mass BCG last weekend before ordering a new barrel. I also have the lighter spring for the JP SCS that I haven’t tried yet.

To jpgolffl’s point, if I need to run a low mass carrier and light buffer spring to reliably run all factory loads with a 20” barrel and +2 gas, what the hell are we doing?

 

[Precision Underground]

I appreciate the discussion. I started this build last winter and just accepted the fact that all the big name builders were running + gas because this was some hotrod new cartridge that overwhelmed standard rifle gas. After running real world loads and struggling with gas issues, I started questioning the philosophy.

My 6.8s run great on mid gas, my 308 is on rifle, my 458 socom is mid, my spr 5.56 is rifle etc.

I forgot to mention that I tried a low mass BCG last weekend before ordering a new barrel. I also have the lighter spring for the JP SCS that I haven’t tried yet.

To jpgolffl’s point, if I need to run a low mass carrier and light buffer spring to reliably run all factory loads with a 20” barrel and +2 gas, what the hell are we doing?

What barrel is it? I’m curious. I’m plotting turning my accuracy AR into a Valkyrie soon.

 

[dang472]

The barrel blank is a Wilson arms 1/7 twist .750 gas block size. The gunsmith is a Hide poster and I haven’t even contacted him about the issue so I don’t want to drag his name through the mud. Since the other barrel he did appears to cycle fine(very low round count), I’m running through all scenarios on my end before making this his problem. If the new Wilson Combat rifle gas barrel runs good, I’ll send this one back to see if he can diagnose the issue.
If there’s nothing wrong on his end, I’ll just chalk it up to a rifle setup that’s way too picky to be a year round field gun.

 

[Precision Underground]

The barrel blank is a Wilson arms 1/7 twist .750 gas block size. The gunsmith is a Hide poster and I haven’t even contacted him about the issue so I don’t want to drag his name through the mud. Since the other barrel he did appears to cycle fine(very low round count), I’m running through all scenarios on my end before making this his problem. If the new Wilson Combat rifle gas barrel runs good, I’ll send this one back to see if he can diagnose the issue.
If there’s nothing wrong on his end, I’ll just chalk it up to a rifle setup that’s way too picky to be a year round field gun.

What does it do or not do when it acts up? Not lock back? Short cycle? How often?

 

[Precision Underground]

Did I read in your other thread that you tried the other identical barrel before and got the same result?but that barrel works fine in your friends gun?

 

[dang472]

Definitely doesn’t lock back on an empty mag. If the turn the gas block in 4-5 clicks it won’t even eject. I thought originally I might have too much gas so I tried turning the gas down. I’m only running reloads now so that throws another variable.
Initially I ran 3-4 boxes of factory 60gr when I first put it together. It was colder out and cycling was hit or miss. Sometimes it would load 4-5 times good, then the carrier would jam the next round into the feed ramps.

The 90gr factory loads were more reliable and stout. They would cycle rounds out of the mag for the most part but wouldn’t always lock back on empty. The dirtier the gun got made everything worse. We’re talking 15-20 rounds. The 60gr loads were really dirty. Some guys on here think Federal uses AR Comp which seems to run dirty in the Valkyrie.

My reloads started with the 52gr Eld to see how fast I could get them. I was over 3300fps and reliability wasn’t good. I had 75gr Elds running almost 3000 and it was a single shot, not locking back on an empty mag.

My gut tells me the gas port is slightly off because there are guys here that are running 18” + 1 Valkyrie barrels without my problems. I hope to resolve this soon because predator season is close

 

[TonyTheTiger]

Have you taken the GB off to make sure the carbon ring is centered over the port?

 

[dang472]

Well, here’s the deal with the other barrel in my friends gun. I’m saying it’s good as of right now because I fired about 10 rounds of factory 90gr through it after I assembled it. At that time, it cycled every round and locked back empty. My buddy hasn’t put a scope on it or tried different ammo since I test fired it. I’m afraid he’ll have similar issues that I did so I’m trying to get this figured out for the both of us. I’d much rather fight it with my gun than have him calling me every weekend.

 

[dang472]

I’ve had the gas block off several times, new gas tube, different BCGs, different buffers (carbine and rifle), different lowers. I bought some sized drill bits to open up the port as a last ditch effort.

 

[Precision Underground]

Well, here’s the deal with the other barrel in my friends gun. I’m saying it’s good as of right now because I fired about 10 rounds of factory 90gr through it after I assembled it. At that time, it cycled every round and locked back empty. My buddy hasn’t put a scope on it or tried different ammo since I test fired it. I’m afraid he’ll have similar issues that I did so I’m trying to get this figured out for the both of us. I’d much rather fight it with my gun than have him calling me every weekend.

That would be crucial info since your gun had the same issue with both barrels. I would not have been able to resist running some rounds through it to see if it worked on his.

 

[dang472]

Yep, I’ve been working out of state for the last 4 months but now I should have time to make sure both of ours are running.

I’ve got the new WC barrel and it’s gas port is 3/32” or .0938”. My current barrel is the same size maybe just a touch looser on the bit.

I took a few pics of the gas block journal. I wonder if his scribe lines are causing gas to leak by. You can see some powder residue front and back of the gas block. I noticed it before but since this is my first all FDE barrel, I figured the color just showed it better.

 

[Precision Underground]

Yep, I’ve been working out of state for the last 4 months but now I should have time to make sure both of ours are running.

I’ve got the new WC barrel and it’s gas port is 3/32” or .0938”. My current barrel is the same size maybe just a touch looser on the bit.

I took a few pics of the gas block journal. I wonder if his scribe lines are causing gas to leak by. You can see some powder residue front and back of the gas block. I noticed it before but since this is my first all FDE barrel, I figured the color just showed it better.View attachment 6941794View attachment 6941795

I wouldn’t think that would be near enough to make a difference. I would measure base to hole on the barrel and on the block to make sure they line up perfectly. He may have meant for you to seat the block even with the little shoulder you see in pic 1.

 

[dang472]

.224” roughly from the back shoulder to the start of the gas port. All of my gas blocks are really close to that distance