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Shot my first AR-15 suppressed today and the gas smell was terrible.

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https://sigforum.com/eve/forums/a/tpc/f/630601935/m/9710042164

September 21, 2019, 09:18 PM
BB61
Shot my first AR-15 suppressed today and the gas smell was terrible.
I was told the gun was wet and it was an auto but still, I don’t know how people could shoot an AR15, with a suppressor, for any extended length of time suppressed. Is this common? For reference it was a Daniel Defense Mk18.


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September 21, 2019, 09:22 PM
creslin
Well for starters you’re running a DI rifle.
Piston guns are less gassy to your face.





This is where my signature goes.
September 21, 2019, 09:27 PM
fritz
I've shot many thousands of rounds through multiple suppressed ARs. So far, I've shot out two AR barrels. Yep, there's blowback with suppressed ARs -- definitely DI, to a lesser extent piston.

The reduced noise and the reduced recoil are worth the trade off to me.
September 21, 2019, 09:28 PM
MikeinNC
Yup, it does introduce more gas into the receiver and thus leaking thru the gaps around the charging handle and you get more to the face.

Most guns are overpassed from the factory so that any ammo will run in their guns. I put an adjustable gas block and dial it wayyyy down to where it will function without the suppressor, when I add the can, gas volume in the receiver increases.

It’s part of the beast. Wear glasses. Or get a piston upper.



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“You may beat me, but you will never win.” sigmonkey-2020

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September 21, 2019, 09:33 PM
BB61
quote:
Originally posted by MikeinNC:
Yup, it does introduce more gas into the receiver and thus leaking thru the gaps around the charging handle and you get more to the face.

Most guns are overpassed from the factory so that any ammo will run in their guns. I put an adjustable gas block and dial it wayyyy down to where it will function without the suppressor, when I add the can, gas volume in the receiver increases.

It’s part of the beast. Wear glasses. Or get a piston upper.


I like the adjustable gas block idea. It sounds similar to the adjustable gas pistons for a M1 Garand shooting modern ammo. I hadn’t thought about the

I hadn’t thought there would be that much of a difference between a DI and a piston.


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September 21, 2019, 09:37 PM
RHINOWSO
With a properly gassed and setup DI AR15, shooting it suppressed can have zero gas to the face.

And I mean zero, having shot ones that 'squirt' gas in your eye every shot.

My 11.5" BCM give no gas to the face suppressed with a Saker-K, Vltor A5H3, and Green Rifle SpringCo, and Geissele ACH.
September 21, 2019, 09:59 PM
SigM4
quote:
Originally posted by RHINOWSO:
My 11.5" BCM give no gas to the face suppressed with a Saker-K, Vltor A5H3, and Green Rifle SpringCo, and Geissele ACH.


It’s funny you mention that as I have a similar BCM setup running a Saker 762 and have no issues either. Same cannot be said for all my guns, that one seems just about perfect though.



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Complacency sucks…
September 21, 2019, 10:14 PM
Andyb
Hold your breath Wink



"Pickin' stones and pullin' teats is a hard way to make a living. But, sure as God's got sandals, it beats fightin' dudes with treasure trails."

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September 22, 2019, 06:15 AM
jezsuiz
I use an adjustable gas block. It’s the way to go if you are shooting a DI.
September 22, 2019, 07:34 AM
sigfreund
You mentioned the smell, not the fact that gas was being blown into your face. If it was really the smell that bothered you, perhaps it at least partially had to do with the type of ammunition. What was it?




6.4/93.6
September 22, 2019, 08:32 AM
Rustpot
Triarc 14.5" barrel with a tight port and midlength gas, an A5 buffer setup, and a Trash Panda- which is a fat can- and there is almost no difference at the user end, other than things getting dirty quicker.

Shooting my Colt upper with the same can, which probably has a pretty wide port, 16" carbine length gas, standard H2 buffer, that thing gasses me out within a few shots. Absolutely brutal.
September 22, 2019, 08:48 AM
ARMT Guy
quote:
Originally posted by BB61:
I was told the gun was wet and it was an auto but still, I don’t know how people could shoot an AR15, with a suppressor, for any extended length of time suppressed. Is this common? For reference it was a Daniel Defense Mk18.


The first suppressed AR I fired was also a MK18 that our rental range had at the time. My impression was like having my face in front of a car's exhaust pipe while the person at the wheel revved the engine. Alot of MK18s were built with larger than standard gas ports due to customers complaining that their el-cheapo commie steel cased .223 wouldn't reliably cycle the action, but as others have said, many DI ARs are typically over-gassed.

I would recommend going the piston route too, if you decide to get into that.




"Also I heard the voice of the Lord saying who shall I send, and who will go for us? Then said I, here am I, send me."




September 22, 2019, 09:09 AM
RHINOWSO
It is highly dependent on the rifle setup (DI / Piston / Gas port size / adjustable gas block / Buffer setup) and Suppressor (brand, caliber, etc).

Often times 762 suppressors on 556 rifles will do better since they normally have more volume and take more of the gas.

An anti-gas charging handle (Geissele, Gasbusters, etc, etc) can also help deflect the gas up and away from the shooters face.

It definitely SUCKs when you have an overgassed rifle spitting gas in your eye every shot, but it can and should be overcome by the owner with proper rifle setup.

The first place I would start is a charging handle and a heavier buffer / spring setup. After that, think new gas block / port size, or an adjustable.

Yeah, you can go piston but honestly I think piston ARs will be forgotten long from now. I'd take an adjustable gas block DI before a piston - my Noveske 14.5 switchblock works great in suppressed but also functions fine in normal with the suppressor, although there is more gas the Geissele CH goes a good job of vectoring it away.
September 22, 2019, 09:19 AM
Chowser
I built my 6.5G SBR with a bleeder/adjustable gas block for suppressed shooting. It works great. I’m slowly switching all my other builds over to it. My 5.56 sbr currently has a vent in place of the forward assist and I did the silicone thing to the bcm charging handle. It doesn’t seem to gas much but I plan on switching this over next.



Not minority enough!
September 22, 2019, 09:32 AM
Rustpot
If you don't want to deal with an adjustable block you can (or have someone) install an orifice in the gas block of the proper size. It can be done with practically any gas block.
September 22, 2019, 11:01 AM
JoshNC
All suppressors and AR15s are not created equal. An AR15 with a proper gas port combined with a low back pressure can like a Surefire SOCOM RC or DeadAir Sandman K is a pleasure to shoot suppressed. Anything AAC, SilencerCo, and many others have much higher back pressure and require a rifle with a small gasport to be comfortable.

Adjustable gas blocks are okay. There are none that currently both function well and don’t have issues with wandering adjustment. The better solution is the Gemtech suppressed bolt carrier. It works great, but it does require a proper sized gas port, not the huge blow hole found on many commercial spec ARs.

A suppressed firearm is a system and that system requires that all variables in the system are optimized for proper function.

My current favorite setups for shooting suppressed include:
* Colt m4 socom barrel, standard LMT bolt, LMT eCarrier, h3 buffer, carbine recoil spring.
* Same as above with A5 receiver extension, A5H3 buffer, rifle recoil spring (my friend’s)
* LMT mrp 10.5 DI, standard LMT bolt, Gemtech SBC, h3 buffer, carbine recoil spring (my friend’s)

My current personal favorite cans are:
* DeadAir Sandman K with 7.62 flash hider endcap
* Surefire 762 SOCOM RC
* KAC QDC CQB 762 (owned by a friend)


Here is a video of one of my friends shooting the third setup noted above on my Colt M16 lower. Suppressor is a SiCo 762 Saker, which is a higher backpressure can but way less so when shooting 5.56. We no longer shoot that can, having moved essentially completely to the DA Sandman K.

https://m.youtube.com/watch?v=1SdWE5y-F3w

And a slow motion video of me shooting:

https://m.youtube.com/watch?v=d5eI8TswUFg

As an aside, I HATED my SCAR16 when it was in stock form using an AAC M4-2k08. It was painfully gassy. Tons of carbon and gas in your face. Then I swapped to a smaller gasport (gas jet) and it was delightful. It’s now a SBR with factory 10” barrel and a smaller factory gas jet tuned to use my SF 762 SOCOM RC such that with m193 it won’t lock the bolt back when set to suppressed without a can installed, but will lock back with the can installed. Now it’s perfect because the system is tuned.

This message has been edited. Last edited by: JoshNC,


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"AND YEA THOUGH THE HINDUS SPEAK OF KARMA, I IMPLORE YOU...GIVE HER A BREAK, LORD". - Clark W. Griswald
September 22, 2019, 01:57 PM
DaBigBR
I have a 6933 that has a Gemtech suppressed BCG and gas buster charging handle. It is amazing.
September 22, 2019, 02:07 PM
mew
my 11.5" Colt SBR has zero blowback, as Rhino said when they have a properly sized gas port with a proper spring and buffer combo they are great.


"All that is necessary for the triumph of evil is for good men to do nothing"
Edmund Burke
September 22, 2019, 02:07 PM
arlen
Adjustable gas block is the way to go. It will eliminate the problem to a large degree if you are not a trail hound.


Regards,
arlen

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Some days, it's just not worth the effort of chewing through the leather straps.
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September 22, 2019, 02:08 PM
BB61
quote:
Originally posted by sigfreund:
You mentioned the smell, not the fact that gas was being blown into your face. If it was really the smell that bothered you, perhaps it at least partially had to do with the type of ammunition. What was it?


I didn’t pay that close attention to the ammo as I was just shooting and wasn’t paying for anything. It was a green and white box. I want to say I saw an eagle so maybe Federal????

The smell was what was blowing in my face. No particulates on my glasses or shirt.


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