View Full Version : AR-15 "gas in the face" question

May 22, 2010, 06:48 PM
OK, I will frame this by stating that I do not ahve a single DI Ar-15 weapon currently. It has been quite awhile since I have fired a DI ar-15 weapon. I do have some piston ar's and some none ar 556 weapons, but none are DI. I am curious about a conversation I heard in the gunstore today (I know, I know...gunshop drivel is humorous at best much of the time). It came up about gas blowback in the shooter's face from the DI system. I overheard both a salesman and another customer were talking about it being a problem with DI ar's. They were talking about gas buster charging handles and all kinds of fixes as if they were a necessity....

I honestly don't remember it being a big deal, or getting a ton of gas in my face because of the DI system. But I haven't fired a DI weapon in so long, I am not discounting the possibility. Sooooo, what say you? What are your experiences with gas in the face from a DI ar? I figure it is only really going to be a problem supressed.

Perhaps a dumb question, but I am in a dumb mood....:D

May 22, 2010, 06:49 PM
Gas in the face is not an issue on my AR's.

May 22, 2010, 06:58 PM
I think they meant gas in the breech face, not their face.

May 22, 2010, 07:10 PM
Let me preface this by saying that I have fired an AR for over 30 years (first in the military and then in competition), and that adds up to many thousands of rounds downrange. In all that time, I have never had gas from the DI system hit me in the face. How could it? The end of the gas tube is housed inside the receiver and the end of the tube is enclosed by the gas key. When the bolt carreier starts to move rearward, the gas tube is open to the ejection port. Following the path of least resistance dictates that the gas will not try to move throught tightly confined spaces. Maybe I'm missing something, but I have never noticed gas hitting me in the face.

May 22, 2010, 07:15 PM
They were talking about the charging handle area...and I do no that gas does escape there, but I do not remember it being "uncomfortable" to fire.

That said, I don't have any DI ar's at the moment, so I have no way to test.

May 22, 2010, 07:23 PM
I always seemed to get something if my rifle was to owet (from CLP) but I think it probably was CLP being sprayed to my eyes-- dont remember gas though..My AR doesn't, but I don't shoot it real wet either...

May 22, 2010, 07:24 PM
They were talking about the charging handle area...

Gun store idjits... There are reasonable arguments to be made for piston vs DI system, but "gas in the face" isn't one of them!

May 22, 2010, 07:25 PM
ONLY if you are shooting suppressed and, the PRI Gasbuster can fix that problem.

May 22, 2010, 07:46 PM
You can get CLP and some gas blown back if you over-lube your weapon. When I am working a line, I know our instructors teach immediate action to the shooters before coming out because I also teach from the same lesson plan. Because they are taught this, I expect them to freakin' perform it when they have a stoppage but sure enough, one of these stellar performers will wind up raising their hand for me to come over there and fix it for them. Fine, I'll fix your freakin' stoppage for you there "warrior" and to make dang sure I won't have to come back over there again! I'll just "lube it up for you" since it's probably dry. A few pumps later, a dripping weapon on the firing line and now it's time to sit back and watch the show when the young airman fires the next round. They are treated to CLP getting blown back in their face and a weapon that smokes like a muzzle loader for the first few shots. The end result is one of two things, either the weapon works for the rest of the day or they figure out how to fix a stoppage themselves but they never seem to raise their hand for me to come over there and fix any other problems. By god, you're gonna learn one way or another, "warrior"!!!:mad:

May 22, 2010, 08:22 PM
Really only a concern if you have a suppressor, and there's ways to fix that (either through a PRI gasbuster CH or just by some creative application of RTV sealant).

It can be an issue for lefties due to the ejection port, but for righties, unless you mount a can, don't sweat it.

May 22, 2010, 08:28 PM
I'm a lefty. One of the reasons I bought a piston driven gun vs a DI gun is that us southpaws DO get gas in the face from the chamber. It's not a show-stopper but it can get annoying and no lefty should ever fire an AR platform gun without eye protection.

Even with the piston run style a southpaw is still going to get a little in/past the face but not nearly as much.

May 22, 2010, 09:21 PM
I have heard about it. On all of my AR's, match or otherwise, I put silicone seal in the half moon area of the cocking handle. Just enough that it is under compression when the handle is fully forward.

I shoot an AR with my nose touching the cocking handle, so I don't want gas leaking around that joint.

Never had a gas leak around the silicone.

May 22, 2010, 10:05 PM
I have definitely had gas in the face from an AR. It is not forceful, as in under pressure, but can definitely smell it. In fact it has become somewhat of an annoyance when shooting long strings, as I like to breath clean air.

May 22, 2010, 10:12 PM
I always seemed to get something if my rifle was to owet (from CLP) but I think it probably was CLP being sprayed to my eyes-- dont remember gas though..My AR doesn't, but I don't shoot it real wet either...

I have only had my AR out a few times. The last time was in the rain. I fired about 100 rounds. On three occasions I had gas/water whatever blown back in my face. Not at high pressure, but it had particulate in it. The first time it was drier and some got in my eye. Even then it wasn't all that uncomfortable, but I definitely noticed. The next two times the rifle was thoroughly soaked and whatever blew back did not blow around my glasses but I could smell/taste it.

May 23, 2010, 09:20 PM
Seems we have a couple of different folks with different "experiences" regarding gas venting at the charging handle. Any other thoughts? I really want to go shoot a DI AR again just to verify!! :D

May 23, 2010, 10:29 PM
I always put a couple drops of oil in thr small holes in the bolt carrier and that's it. I cringe every time I see soldiers squirt CLP into their weapon until it's dripping out all over the ground. Some guys just can't be told though.

May 23, 2010, 10:42 PM
An AR will run for about 200-300 rounds with light oil. Worked ok for garrison troops in the ****shine and salute army, but doesn't work so well if you're really working the girl. And yes, even in the sandbox a well lubed rifle works better than a dry one. The Special Operations, the Border Patrol have known this for years. Now, even the Big Army has figured it out. Here is the Army M4 lubrication study http://www.armytimes.com/news/2007/07/army_carbine_lubrication_070716/ or read AR guru Pat Rogers. http://www.ar15.com/content/swat/keepitrunning.pdf

Yes, my drill sergeants (Harmony Church '85, Follow Me also ISC) inspected mine with white gloves and made me swear to forsake all lubrication, but it doesn't work. Besides, those guys only had a three month course and very little of it is concerning weapons. My BIL is still a drill sergeant and he couldn't tell a direct impingement from a direct deposit.

As for the gas, you smell it after a few rounds. It isn't a big deal. Some guy is just trying to sell you one of those silly gas busters or a piston gun.

May 24, 2010, 10:49 AM
I did not know about a gas problem until I asked someone why they had tape on the back of the rifle. There was actually a lot of carbon under and behind the charging handle. I put a new gas key on and he said it helped. It looked like the key had not been seating correctly. I think when you get into older hard used rifles it probably becomes more common, but is not reported because it really is not a malfunction.

May 24, 2010, 01:02 PM
The problem can be more noticeable on aftermarket ARs where the manufacturor has a gas port larger than spec for a given barrel length.

It's a corner cutting method used by some aftermarket guns so that they run on a wider variety of junk ammo. An overgassed AR will cycle harder than a properly made weapon.

And as stated, SOME silencer/gun combos make the problem pretty unbearable. My main silencer/14.5" barrel combo doesn't hardly gas me out at all.

May 24, 2010, 01:43 PM
I'm not an AR fan, but I've never gotten gas in my face shooting my Colt AR15 or my Carbon 15 pistol. Both are direct gas.

May 25, 2010, 06:14 AM
Not sure why the computer thinks s p i t shine is a bad word.

May 25, 2010, 10:45 AM
I've had CLP splatter me from the charging handle. We were range firing, all the guns going on line got squirted down while shotgunned. Most of the excess drained down to the back of the upper, the first shot sprayed a bit out.

Once the port cover was open, no further issue.

If you haven't gotten splattered on the first shot, I recommend it. It's evidence you will have enough lubrication, and it won't let carbon stick. If you don't like getting oily, smelly, and dirty shooting guns, maybe it's the wrong hobby. :D