AR10 Optimal Gas / Buffer

rlsmith1

Legalize Freedom
Full Member
Minuteman
May 1, 2019
1,350
1,138
Midwest
Has anyone gotten their AR10 to where it will run reliably with or without a suppressor? If so, what setup are you running?

My current setup is a 16” middy 308 with an adjustable gas block and DPMS carbine buffer with a sprinco orange spring. It shoots fine suppressed (Sandman S) but when I pull the suppressor it won’t even eject the empty round. If I turn gas up to cycle unsuppressed then I’m crazy over gassed with a suppressor and it isn’t reliable.

I don’t fully understand what impacts the DI operating system so before I start spending money I’d like to hear if anyone else has a setup similar that has worked well. This barrel shoots pretty well (MOA with M118LR) so I’d like to make this barrel work if possible.

Oh and I’ve got a 18” Criterion in 6.5 CM (adjustable gas, rifle length) I will shoot more in the future so any overlap there would ideal
 

reubenski

Supporter
Supporter
Full Member
Minuteman
Supporter+
Jun 8, 2008
6,993
7,779
To
Turn the gas up and tune it so it will lock back on a light spring and buffer unsuppressed and then find a heavy spring and buffer that will tame the over-gas of suppressed shooting without changing the gas block. Then just swap the spring and buffer when shooting suppressed and unsuppressed.
 

rlsmith1

Legalize Freedom
Full Member
Minuteman
May 1, 2019
1,350
1,138
Midwest
That’s a lot more work than opening the gas block each time… I’ve not had this problem with my small frames so I’m guessing it’s possible?

I have a hunch a longer buffer tube and lighter spring might be the ticket but I don’t know. Would like to avoid a rifle length tube / spring if possible
 

hlee

Sergeant
Full Member
Minuteman
  • Jul 14, 2012
    7,996
    10,390
    44
    TX
    Regardless of the tube length, the distance the bcg moves is the same. A longer tube just means a longer buffer.

    The real answer is to stop being a dirty heathen and shoot suppressed all of the time.
     

    rlsmith1

    Legalize Freedom
    Full Member
    Minuteman
    May 1, 2019
    1,350
    1,138
    Midwest
    I understand the buffer loves the same distance, but if a longer tube is used then the spring doesn’t have to be as tight?

    How does JP solve the issue? I’ve stayed away from the silent capture because it seems like unnecessary $ to spend but I’d like to hear more
     

    TurboTrout

    Two Star General
    Full Member
    Minuteman
    Oct 30, 2020
    5,718
    5,986
    East Coast
    I understand the buffer loves the same distance, but if a longer tube is used then the spring doesn’t have to be as tight?

    How does JP solve the issue? I’ve stayed away from the silent capture because it seems like unnecessary $ to spend but I’d like to hear more

    For a small difference a couple composite spacers work great

    Overall it’s just smoother and disassembled it doesn’t fly apart
     
    • Like
    Reactions: rlsmith1

    msgriff

    Sergeant of the Hide
    Full Member
    Minuteman
    Feb 10, 2021
    233
    258
    Rogue Valley OR
    Probably not an option for you, but the Noveske 7.62 Switchblock barrels come with a selectable gas block. Unsuppressed, suppressed and off. There are other selectable gas blocks for quick gas flow adjustments, Seekins Precision Lever, Strike Industries Collar and the Riflespeed to name a few. Some of these require specific handguard specs.
    Also, if your AGB requires side access or uses stacked or double adjustment/lock screws. consider getting an AGB with a front access detent type adjustment screw and use a long ball end hex driver.
     
    • Like
    Reactions: rlsmith1

    hlee

    Sergeant
    Full Member
    Minuteman
  • Jul 14, 2012
    7,996
    10,390
    44
    TX
    I think that most people doing large frame gassers just accept that a gas setting change will be required when going from suppressed to unsuppressed. You can get away with a little overgassed in a small frame (300 BO, 5.56, Grendel all work like this for me). But you just have too much gas to mitigate from a large frame gun. Check out the RifleSpeed gas control gas block. You must make a change, but the change is pretty easy. I don’t have one, so no first hand experience.

     

    rlsmith1

    Legalize Freedom
    Full Member
    Minuteman
    May 1, 2019
    1,350
    1,138
    Midwest
    Thanks guys! I’ll stick with my SLR blocks as I can change settings pretty easily
     

    bigjake83

    Golden Shellback
    Full Member
    Minuteman
  • May 19, 2013
    3,879
    1,669
    Southern Idaho
    Thanks guys! I’ll stick with my SLR blocks as I can change settings pretty easily

    Screenshot_20220808-140229.png
     
    • Like
    Reactions: rlsmith1

    GhostFace

    Sergeant
    Full Member
    Minuteman
  • Apr 1, 2003
    1,267
    492
    46
    Indiana
    Narry a problem with any of my Armalites, the only thing I added was a Tubbs Flatwire spring and a adjustable gas block. Neither were "needed" but it made shooting Suppressed better. My brass no longer has swipes and the primer pockets are tight. I'd say if your having problems I'd go with the Armalite/A5 buffer tube and a H3 buffer at minimum.

    ETA mine are all RLGS even the 16 incher. I would never go with a midlength.

    Also I don't like the switch block types, you're limited on your adjustability. I like the ones you can fine tune because not every gas port is the same size.
     
    • Like
    Reactions: rlsmith1

    JimmyT

    Private
    Full Member
    Minuteman
    Feb 25, 2017
    251
    70
    I use an aero precision AR10 buffer (2.5”/3.8 oz)and a springco “white” spring for my AR10 with carbine length buffer tube and 16” Wilson combat 6.5 creedmoor barrel. I also have a SLR 7 AGB on the rifle. I turned down the gas until I get a 4-430 ejection unsupressed and get a 130 ejection pattern when running my suppressor. It runs great with my hand loads and that is the best I can ask for!

    once I had the rifle “tuned”, I quit playing with it and shoot the crap out of it. In my experience, the JP SCS didn’t give me the results I was looking for. ION I bought a “used” AR10 that was sold due to the previous owner giving up trying to make it run. The price was right so I bought it. On initial disassembly I found a rifle length spring and a H4 buffer in it. It shot like a musket, needing to manually rack the rifle to chamber and fire the next round. That was a bear to work with and ended up returning it to the manufacturer for warranty repair.

    your mileage may vary… and good luck setting up your rifle.
     
    • Like
    Reactions: rlsmith1

    TonyTheTiger

    Like a Boss
    Full Member
    Minuteman
    Feb 14, 2017
    3,775
    4,886
    So how far out can you go on a 16” 308 and maintain reliability? R+1? +2?
    RLGS 16" 308's are a well known reliable system. Plenty of barrels out there and the Sig 716 adopted by the Indian army uses it. Not saying I give a shit what India uses, just saying borderline reliable systems rarely make that far.
    I might try a RLGS +1", but that's just because I'm silly like that.
     

    rlsmith1

    Legalize Freedom
    Full Member
    Minuteman
    May 1, 2019
    1,350
    1,138
    Midwest
    Thanks all, I'm hesitant to run a lighter spring because I love the authority the with which BCG goes into battery with sprinco orange but glad to hear you've had good luck with a lighter spring @JimmyT, I may give that a try.

    @TonyTheTiger I would buy another barrel for sure but this stupid ballistic advantage barrel puts factory 2nd M118LR sub moa for 10 shots! I've considered chopping it to 13" or 14.5" and getting a good rifle gas 308 barrel but if I'm going to shoot quality I'll run the Criterion upper in 6.5
     
    • Like
    Reactions: TonyTheTiger

    JimmyT

    Private
    Full Member
    Minuteman
    Feb 25, 2017
    251
    70
    In my limited experience, the springco springs are really beefy and possibly overpowered for the application. This isn’t a bad thing, just something to consider. When “tuning” a big block AR, I like using the springco products since they have a predictable compression and defined spring power levels.

    YMMV
     
    • Like
    Reactions: rlsmith1

    NCHillbilly

    Libertata Aut Morte
    Full Member
    Minuteman
  • Jul 7, 2012
    1,018
    1,343
    The occupied states of America
    I recently built an 18" 308, and am dealing with almost the same issues. It also is a mid-length gas tube, which was the only option with the BA barrel. It has shown great accuracy since first firing, but the bolt never locked on a empty mag until I put the muffler on it. Suppressed, it runs flawless.

    I am using a KVP 5.6oz buffer with the sprinco orange spring. I think to fix my unsuppressed issues, I'll try either a slightly lighter spring, or remove 1 weight from the buffer and see what happens.

    With the GB opened all the way up, it was very close to being fully functional, except for bolt lock back. With suppressor on, I needed to cut the gas down, but it ran perfect.
     
    • Like
    Reactions: rlsmith1

    KineticPerformance

    Private
    Full Member
    Minuteman
    Feb 15, 2017
    240
    135
    My answer to the dual gas issue is an OSS can. I can run them the same as unsuppressed and they only move a half clock position with no change to accuracy/precision/reliability.
     

    Bigtrucknut

    Private
    Minuteman
    Dec 9, 2020
    55
    31
    NoVA
    What diameter is your barrel's gas port? An adjustable gas block can't work correctly if it doesn't get enough gas through the barrel gas port. Sounds like it is too small and needs to be opened up a little to get reliable functioning (bolt lock open on last round) when running unsuppressed.
     

    rlsmith1

    Legalize Freedom
    Full Member
    Minuteman
    May 1, 2019
    1,350
    1,138
    Midwest
    What diameter is your barrel's gas port? An adjustable gas block can't work correctly if it doesn't get enough gas through the barrel gas port. Sounds like it is too small and needs to be opened up a little to get reliable functioning (bolt lock open on last round) when running unsuppressed.
    No idea but it’s over gassed without a doubt. That’s why I put the adjustable block on there to start. It wasn’t locking back on an empty mag without a suppressor because I had turned the gas down to be better for a suppressor
     

    NCHillbilly

    Libertata Aut Morte
    Full Member
    Minuteman
  • Jul 7, 2012
    1,018
    1,343
    The occupied states of America
    Don't know if it'll help your situation, but I finally got to shoot mine after removing one weight (1.5 oz's) from my KVP buffer. Other than having to change my gas block setting, it now runs pefectly.

    Think I'll leave it alone now, and just shoot the shit out of it.

    edit: change my gas block setting depending on running suppressed or open, with no other changes
     
    Last edited:
    • Like
    Reactions: rlsmith1