AR10 barrel and gas system advice

[BoulderE89]

I know this has been hit plenty of times on the forums but im an over thinker so im gonna ask you to help me get this sorted in my mind so I can stop thinking way too hard about it. budget for the barrel is $400

I am slowly building an AR10 in 6.5 CM on an aero receiver set. I am at the point now where I need to decide my barrel and gas system combination. I have 2 main combinations I am interested in...for reference im planning to use a 15" odin works m lok handguard.
1. Wilson combat Super sniper 22" with a rifle length gas system and a JP adjustable gas block where the adjustment screw is recessed in the handguard on the side of the block
2. X caliber 22" barrel with +2 gas system and the same gas block but its sitting out in front of the handguard now

My over thinking is coming at the fact that I dont know how important that +2 gas system is for a 22" barrel. If its needed then I need to go with an x caliber. But if I can make a 22" barrel work with rifle length through things like an adjustable gas block and buffer and springs in the lower, then I have heard great things about the wilson combat and would love to try it. any advice and first hand experience on these type of builds would be greatly appreciated. I have built precision AR15's before, but I know precision AR10s are another beast with its own separate challenges.

 

[RyanScott]

I’ll put it this way: a rifle gas system is a wobbler on a 16” barrel. It’s doesn’t belong on anything longer. Period.

 

[Powder_Burns]

My 16” 308 has a midlength gas port, running the jp adj block and an odin works lite 15” handguard. The adjustment screw is partially obscured by the handguard, but still able to adjust the screw with a regular allen key. A ballhead key may work better, or I could have milled away some more clearance. Not that big of a deal for me.

 

[drewthebrave]

I recently went down this rabbit hole, and settled on the conclusion that while an extended gas system would be preferred, a properly sized Rifle-length gas port with an adjustable gas block should function just fine. I would let the primary decision factor be the overall quality of the barrel, with the gas system length being of secondary concern.

For what it's worth, I was 100% ready to go with a 20" Faxon Heavy Fluted barrel with rifle-length gas system for my Creedmoor build. Right before I went to buy the barrel, I came across a very good deal for an 18" Craddock Precision Criterion heavy barrel with +1" gas system. While the extended gas system was a nice bonus, I bought the Craddock Precision barrel based on the company's reputation.

In the case of the 2 barrels you're considering, I think they are pretty comparable as far as quality. I'd lean towards the maker that you feel has the better reputation for quality & accuracy. While a +2" gas system might help tame the recoil impulse & improve reliability, I don't think that a rifle-length gas system is a handicap IF you use an adjustable gas block. NOW - if you plan to shoot suppressed, the extended gas system would be of great benefit. If not, I'd say it's a toss-up.

TL/DR: Choose based on barrel quality first. Gas system length can be beneficial, but is is of secondary importance.

 

[celltech]

I built a 6.5 AR with a Criterion 22" and a rifle length gas system. My Odin Works adjustable gas block was not able to dial down low enough to control it, but a SA bleed off block was. The 6.5 has quite a bit more port pressure than the .308, but it can be controlled with the right system. So I would say the gas block is more important than the tube length in this scenario.

 

[BoulderE89]

I built a 6.5 AR with a Criterion 22" and a rifle length gas system. My Odin Works adjustable gas block was not able to dial down low enough to control it, but a SA bleed off block was. The 6.5 has quite a bit more port pressure than the .308, but it can be controlled with the right system. So I would say the gas block is more important than the tube length in this scenario.

So the 6.5 pressures would make a rifle length system plausible? I believe both slr and jp gas blocks should be able to go down enough to control the gas, they have good reputations too.

and yeah I forgot to mention but this will be primarily suppressed when shot. Not a guarantee tho

 

[Forward543]

I have built both. The longer the gas system, the easier life is. You can tune a 22" rifle length to work, but a longer system is easier. Not a deal breaker, but when switching between suppressed and un, it is nice if the pressure is in the right spot

 

[MNhunter1]

I have two 16" 308s with midlength gas, both with SLR adjustable blocks. In my opinion, the +2 gas is not necessary. I would absolutely recommend running an adjustable block on any large frame AR platform. I would give SLR a call and pick their brain a bit, or even Wilson Combat and X-Caliber in regard to their barrels and gas porting.

 

[Bullspotter]

I opt for the longer gas systems on the high pressure rounds, I kinda learned the hard way, Built a 260 AR-10, Was getting major pressure issues with starting loads, Running light carrier and buffer, with adjustable gas block. accuracy was OK but velocity was poor. Built several high end AR15s for 3 gun, found AR10s are not the same animals.

Ended up selling BBL, and got a Kreiger bull with a longer gas tube, Also got the heaviest carrier i could find, and a tubbs carrier weight, also swapped out gas block and got the superlative one. Talk about a difference, I have also a 6 creed and 2nd 260 now, Both with Proof carbon BBL with +2 or +3 gas I cannot remember. Also with heavy carriers and superlative gas blocks. they run awesome with good velocity, and easy on brass. I talked with Several guys who have built high pressure gas guns, (PRS GUYS) and was told the lockup time is important to not tear up brass and keep pressure signs down. I may or may not be right about my thoughts on this, but i do know my 3 AR10s run and shoot great. I am also running JP high pressure bolts in them, But not JP carriers.

 

[Forward543]

.308 is much more manageable with a rifle length. The 6.5 is higher pressure.

 

[BoulderE89]

Sounds like if I’m gonna use my suppressor and want to continue reloading my brass then x caliber will be the easier way to go with those two factors in mind.

 

[drewthebrave]

Sounds like if I’m gonna use my suppressor and want to continue reloading my brass then x caliber will be the easier way to go with those two factors in mind.

The extended gas system is going to make your life with a suppressor much easier.

 

[rlsmith1]

Old post but sounds like a few of you know the ins and outs of DI guns.

I have a 18” 6.5 CM with rifle gas (adjustable gas block), and Sandman S. Is there any hope for me to get it to run both suppressed and unsuppressed on the same setting?

Currently, I have not found a sweet spot for both but can make the gun run very smooth if optimized for one or the other.

I have a carbine tube with a shortened buffer (3.8oz I believe) with a sprinco orange. In order of preference, I see my options as (1) fine tune what I have for specific ammo, (2) play with gas / spring / buffer weights, or (3) possibly buy a new barrel that is an 18” tube with a +1 gas system. Am I missing anything, and where would you start?

Finally, I’d really like to keep this barrel because it shoots very well

 

[bigjake83]

Old post but sounds like a few of you know the ins and outs of DI guns.

I have a 18” 6.5 CM with rifle gas (adjustable gas block), and Sandman S. Is there any hope for me to get it to run both suppressed and unsuppressed on the same setting?

Currently, I have not found a sweet spot for both but can make the gun run very smooth if optimized for one or the other.

I have a carbine tube with a shortened buffer (3.8oz I believe) with a sprinco orange. In order of preference, I see my options as (1) fine tune what I have for specific ammo, (2) play with gas / spring / buffer weights, or (3) possibly buy a new barrel that is an 18” tube with a +1 gas system. Am I missing anything, and where would you start?

Finally, I’d really like to keep this barrel because it shoots very well

3.8oz is way too light, you should be running a H2 4.65oz at a minimum. I run H2 on all my rifles and I don't use suppressors.

This is what you need..

This rifle is a 18" 6.5CM with rifle length gas..

 

[rlsmith1]

3.8oz is way too light, you should be running a H2 4.65oz at a minimum. I run H2 on all my rifles and I don't use suppressors.

This is what you need..

View attachment 8094888View attachment 8094889

This rifle is a 18" 6.5CM with rifle length gas..
View attachment 8094890

Thanks! I made some adjustments today and am able to run suppresses and I suppressed without changing gas settings.

For those reading in the future… I started with a shortened buffer to run a 308 carrier in a standard tube. This was way too light for what I was after (one setting for suppressed / unsurpassed), and was chewing brass a bit.

Due to this thread and a couple others, I swapped to an A5 tube, standard H2 buffer, and regular AR10 spring. I returned for gas and I’m now running suppressed (Sandman S) and unsuppressed on the same setting. If I wanted to get picky I could say I’m over gassed suppressed but it’s not enough to impact reliability as of yet. Temp was mid 40’s and gun wasn’t particularly clean so I feel good about it running in various conditions.

In short, my 18” 6.5 Creedmoor with rifle gas runs great with a standard (A5) tube, standard spring, H2 buffer, and adjustable gas

 

[bigjake83]

Thanks! I made some adjustments today and am able to run suppresses and I suppressed without changing gas settings.

For those reading in the future… I started with a shortened buffer to run a 308 carrier in a standard tube. This was way too light for what I was after (one setting for suppressed / unsurpassed), and was chewing brass a bit.

Due to this thread and a couple others, I swapped to an A5 tube, standard H2 buffer, and regular AR10 spring. I returned for gas and I’m now running suppressed (Sandman S) and unsuppressed on the same setting. If I wanted to get picky I could say I’m over gassed suppressed but it’s not enough to impact reliability as of yet. Temp was mid 40’s and gun wasn’t particularly clean so I feel good about it running in various conditions.

In short, my 18” 6.5 Creedmoor with rifle gas runs great with a standard (A5) tube, standard spring, H2 buffer, and adjustable gas

What's the ejection pattern of your brass suppressed and unsuppressed?? If the brass while suppressed is between 2-3 o'clock and unsuppressed is between 3-4 o'clock you're golden.

Also take a look at your case heads for ejector or extractor marks, id still pick up a H3 buffer and give it a go.

The rife I posted above is running a 18" 6.5CM Bartlein with Rifle Length Gas, Full Mass BCG, H3 JP SCS with heavy red/yellow Spring and a adjustable gas block. I tried running the H2 but i was getting substantial case head swipes with Hornady Match ammo so I popped in another tungsten weight for the SCS and now everything functions perfectly and my brass is clean.

 

[rlsmith1]

What's the ejection pattern of your brass suppressed and unsuppressed?? If the brass while suppressed is between 2-3 o'clock and unsuppressed is between 3-4 o'clock you're golden.

Also take a look at your case heads for ejector or extractor marks, id still pick up a H3 buffer and give it a go.

The rife I posted above is running a 18" 6.5CM Bartlein with Rifle Length Gas, Full Mass BCG, H3 JP SCS with heavy red/yellow Spring and a adjustable gas block. I tried running the H2 but i was getting substantial case head swipes with Hornady Match ammo so I popped in another tungsten weight for the SCS and now everything functions perfectly and my brass is clean.

I'm about 4 or 3:30 unsuppressed and closer to 2 or 1:30 suppressed. I'd like to bring it back one click, but I don't get bolt lock back unsuppressed then. I could go to H3 but I don't have an extra weight to do that so I'm happy with where I am. If I start experiencing issues I may explore further