The heart of the AR-15 is its simple, robust direct-impingement gas system. But if the gas ain’t flowin’ right, your rifle will malfunction. Brownells Gun Techs Caleb and Steve share some tips for figuring out what’s wrong. First, determine if your AR is over-gassed or under-gassed. Is too much gas flowing or not enough? The key is to watch how your rifle ejects spent shells. On a properly functioning AR-15, they should zip out of the ejection port at about 3 to 5 o’clock. If the shells eject FORWARD, your rifle is OVER-GASSED because the shell isn’t clearing the ejection port before the bolt closes again. Easiest solution for over-gassing: install an adjustable gas block and dial back the gas flow. (Alternate fix: try a heavier buffer.)
Short-cycling or not fully ejecting spent casings is usually a sign of being UNDER-GASSED. Make sure the gas block fits snug on the barrel’s gas journal and the gas tube fits tightly into the gas block. If either is loose, gas will leak and there won’t be enough left in the system to cycle the action properly. A loose gas key on the carrier will also cause a loss of gas pressure. This is why you always want the screws on the gas key tightened down and “properly staked.” And if the gas tube isn’t correctly aligned with the gas key, it can wear the key over time, causing another gas leak. Finally, check for worn out gas rings on the bolt. Caleb shows us his handy trick for determining if the gas rings are worn. If these fixes don’t solve your gas system problem, we’ll be flabbergas…. ted!
Custom sized gas tube is even better than an adjustable gas block
If the buffer is getting trap on the spring does that mean that it's over gas?
Can you talk about the what I call the kicker system , no gas tube, but a rod to kick the bolt carry group back. The question is, is it easy to clean , does it work as well as the gas system and the life of these system.
Learned something today
Thank you
Great stuff as always. Especially the simple test of the gas rings.
Great 👍🏻 keep doing it👍🏻
Little tip. A dab of blue loctite will stop your gas leaks. 💙
I have known a lot of shooters that were die hard convinced that the gas rings on the bolt had to be aligned. I have even pulled out metal pins, cut to length, that someone put in to keep them aligned.
Great video!!!!
0:43
If your gas rings are worn out, might it be better to just buy a whole new bolt?
You guys are great. I am new to the AR platform and have learned a lot. Please keep it up! Thanks
When I eat Taco Bell I'm overgassed
Much better Steve…damn hippie.
My wife’s 18” AR sends them at 12:30…unsuppressed-waaaay over gassed but it takes out the bad guys’ buddies. I’m too lazy to change out gas blocks, what’s everyone’s experience with adjustable gas bolt carriers like Bootleg or Gemtech?
Would that also apply to a Springfield M1A .308. My shells end up in front of the bench
Best gun videos are with these two. Great job, guys!
Ask any of my friends that hang around with me and they will tell you that I am deffinately way over gassed LOL,,,,with no fix in site LOL.
Can you do a video on getting an old single-shot break open shotgun up and running. There are a lot of these shotguns sitting in peoples closets but they might need a new firing pin or have a cracked stock or something. Where do you get those parts? How do perform some of the common parts replacements?
Great tips!
Hard to wear out anything without ammo.
what about gas port erosion and/or gas block erosion if the gas block is aluminum?
Thanks for the info
I had a 300BLK pistol that had a feed issue that I've never seen before. It would fire, extract and eject just fine, but when it went to strip a new round out of the mag, sometimes the round would go up and wedge itself up against the receiver instead of going straight forward into the chamber. I tried multiple different magazines and ammo types and even put a heavier buffer in it to try to slow the bolt down a bit. Nothing seemed to help much. Ever seen this before?
Pic: https://photos.app.goo.gl/mKMcLgpSCdtjqfK59
was that Steve seen leaving a 7-11 after the purchase of 4 bottles of black shoe polish? does he really own so many shoes? LOL
I hate it when I’m leaking gas.
I had a buffer come apart one time causing crazy stove pipes when I first got my ar and took me a cpl days to figure out
Your intended application may also factor into determining if you are optimally-gassed. If you intend your rifle to primarily be a defensive rifle (I'm staking lives on it) then if you can't be optimally-gassed be a little over-gassed. Many military guns are purposefully over-gassed so that if you have a crappy batch of ammo or your gun is fouled up it can still cycle in poor conditions. If you are a consistent competition shooter many of them under-gas their rifles to decrease felt recoil believing it makes them faster. This will decrease reliability so many of them use only match or other highly reliable ammo if they don't hand load, working to find that tipping point between barely reliable with their chosen ammo and short-stroking.
Always great tips, thanks !
Fellows – Simply a quick note to thank you for these tutorials. They are very well done and every time I watch, even when they don’t directly apply to me, I learn valuable things.
I didn’t know the ar15 can work with just one gas ring. Interesting.
AR10 was over gassed and adjustable gas block fixed it beautifully. But before I did that I tried to do it with an adjustable heavier Buffer that didn't work and not only is it hard to find for the AR10 they can be just as expensive as the Adjustable gas block just get the one that works.
I got a barrel for A.R. 15 I was building and was having issues, come to find out (thanks to Brownells and the tec line) the gas port hole in the barrel was drilled too small so I had to drill it out. My butt was tight the whole time I was holding that drill 😆 but now the gun works gr8.
I had a Smith and Wesson M&P10 that was under gassed. I could not figure out why. It would short stroke even with the hottest 308 loads. After weeks of testing different ammo, and taking it apart more times than I can count, I discovered that the gas port in the barrel was actually the wrong size. It was far smaller than factory tolerance.
Ive also noticed in the past year that imported steel case ammo (tulammo, wolf, red army) have had a lot of underloaded rounds. More than usual. So you might get some short stroking from imported steel cased ammo with a properly gassed system. Some AR's have larger gas ports that are overgassed on purpose to cycle these lower end type of ammunition though. So it all depends on how your AR is.
300 blk out is a little different, I had an extremely under gassed one and it was throwing around 1 to 2 o'clock but not far out….had to increase the gas system and change to a 300 blk out buffer spring…..
I feel like Steve is like that proud dad who taught his son well about firearms so now he just sets back in honor watching his son tell the tales of a rifle 😂
Very helpful information, thank you.