Explaining The Gas System On An AR15
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- čas přidán 12. 05. 2021
- The gas system on an AR15 can be very confusing. Gas tube lengths, gas block diameter, buffer tube setup, and which barrel ties it all together?
We wanted to throw this video together to help explain it. Now this won't cover every single scenario because well, that would take forever. So if you have a specific question feel free to leave it below and we will try to help you out!
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All information provided is merely for entertainment and informational purposes. Should you decide to act upon any information provided, you do so at your own risk. Midwest Gun Works does not accept any liability for any mistakes, errors, or faults that may occur. Refer to the manufacturer for specifications of the products used. It is recommended that all modifications or repairs be done by a qualified Gunsmith. - Sport
Nice video. My following comments do not take away from the quality of the video. I would have like to have heard about the following:
(1) what to do when build is “over gassed” or the bolt will not open all the way.
(2) the pros and cons of adjustable gas blocks
(3) the effects of suppressors on gas flow in classic, non-piston driven builds.
When talking about under or over gassed, I would go with an adjustable gas block. The only cons would be price, but it can help you fine tune a rifle very nicely. You will see this very helpful with suppressor set ups, as they can be effect the gas blow back significantly.
In the video we listed the gas block size .836. The actual size for the gas block is .875. Sorry for the mess up folks! If you have any more questions, let us know!
Changed my notes haha good video
Thanks, That threw me. Mine is .875 !
Here's my question. I got an 18 inch 308 Barrel from a friend, he has no info on gas port size or gas length. How do I determine both length and gas port size? I'd assume calipers would help me figure out gas port but I have none. Could I take a measurement from base of barrel to gas port hole to determine length? And with that info would it help me determine gas port size?
I messed up and mixed my buffer springs together in the same storage box. How do I determine which spring is a Pistol spring and which spring is a Rifle spring? this question is for both AR-15 and AR-10.
Just to be clear you can also mix and match gas length and buffer aswell. For example you can run a rifle length buffer stock with a mid length gas system works great! With out an adjustable gas block. The same way you could also use a carbine buffer stock with a heavier weight h3 and pistol length barrel and adjustable gas block and you can cycle no problem with minor adjustments
Great information on this subject - all in one video, thanks!
Thanks Frank!
Awesome. Loved this. Want to build my first AR from the ground up. This helped a ton!
Great video! Very informative and you make it easy to understand.
I can not believe you actually told these viewers that a rifle length spring and buffer can be used in a carbine buffer tube. Maybe you should try that set up an post a video of how well it works for you.
Not only that, but he puts the buffer in backwards in the tube, maybe it was just so it wouldn't fall out of the spring, but he should have told all of these noobs that... smh
Very comprehensive breakdown. Thanks
Kinda cleared up some questions I had.
Considering putting together a PSA, PA10, but got confused when looking at separate complete uppers and lowers.
Might just be better off buying a kit.
this answered all of my questions, thank you so much for this video.
the best explanation video ever about the topic ... we really appreciate you bro.
Thanks. Very well explained.
Thank you. We appreciate that!
This is supper informational great job
Thank you Roger!
Thanks a ton for the explaination!
Very informative to a novice builder, thank you
Great content! Thank you!
Great information. Thank you
awesome! super helpful thank you
trying to make a ar15 chambered in 5.45x39 and wanting it in a pistol form while also having a bit longer barrel for a little more velocity which will be carbine rifle. I'm just confused on what gas is perfect and trying to understand the different effects on close, mid, and end barrel gas choices.
Great video. Question, just added a heavier buffer spring in my A2 M16 clone but with the suppressor I’m still get the hard slam from the buffer. Can I add tungsten weights in the rifle buffer as you can the carbine to slow the buffer? Thanks for the great info.
This was awesome, thanks.
You said its ok to use a carbine length buffer tube on a rifle length gas system for AR10... Any potential cycling issues that this could cause?
On a rifle length gas system on an AR10 build is there an advantage to running a rifle length extension tube and buffer over a carbine buffer tube and corresponding buffer or does it not really make a difference?
I have a 20" M16 style AR-15 with a rifle length gas system.
I want a conversion to either .350 or .450 but it seems that rifle length .350 or .450 uppers are extremely rare. Few are mid-length, most of carbine-length.
Are there any alternatives ?
This was a very informative video. So from what I'm gathering, for my ar10 308 pistol build starting with a 7.5" barrel I'd need a pistol length gas tube. Would I also still need a pistol length buffer spring and tube or would that be effected by the 308 caliber?
Also does that determine what direction I need to head in the gas block?
Pressures may be different due to the .308 caliber. Not sure though. I would call a reputable Gunsmith.
Thanks for the easy explanation simple
I’m running a 14.5 barrel so the right gas line would be mid length? And what buffer should I get?
Also you missed the fact that they sell adjustable gas blocks . I only use them on my barrels so I can tweak and tune my guns to my reloading rounds
Great information
Nice video Thank you
Thanks for watching Carl!
Watched the entire video and it seems you explained everything except the theory behind how & why the gas tube system works.
Oh well, I still gave it a thumbs up because now I am qualified to determine the correct size and length if all those thingamajigs. ;-)
Never heard you mention gas port hole size and how it might come into play.
So I currently have a Del-Ton ar15 with an 18” barrel. I still want to keep the 18” barrel size. Anyway, I fully built the lower and I purchased a G3 Competition Enhance BCG CopperHead bolt carrier (light weight skeleton BC). Now I obviously can’t use it yet until I upgrade the gas system/buffer tube, but I am still wanting to shoot 223/556 (as I can do that currently). What would you recommend getting? I didn’t see anything mentioning an 18” only a 15”, but I would like to get the same barrel length or at the minimum of a 16” length. I believe I was looking at JP, but need more info on what is best. Preferably an adjustable gas block, as that is how I can go from 223 to 556 caliber (at least I think that is how that would work). Still new two this platform. I’ve had mine for just over a year as of February. Any tips would be great! Also I prefer to do everything myself, if at all possible without having to go to a gun smith.
Hey I know I'm late to the video, I was just talking to a guy in a gun store while I was looking for grips and stocks and things like that, I just got my first ar, and he said on my mil spec ar15 a2 clone from Delton that I can't put any longer than a 7 inch handguard over my existing gas block and gas tube setup. I was looking to do a 13 inch m Lok handguard but do you know if he's correct or where I could find more info? Or is there some sort of slim gas system I could put in that wouldn't interfere with the free float handguard? Thanks!
Do all 4 of these lengths work with both piston and direct impingement?
Excellent video. You should make one building an entire AR.
Question If a barrel measures at 11 inch would you put a carbine length gas system on it what or would you use at mid-length what would be best
Good video!
Buffer lengths and gas system lengths don't have to match. All you have to do is adjust your buffer weight if there are problems.
will pistol length work for a 5 inch barrel micro build in 300 blackout?
Any suggestions for pistol length buffer tube system?
What about 16" barrel with pistol length gas tube? What size buffer tube there? My 300blk Aero Precision upper is pistol length .750, but wont cycle sunsonics with default tube assembly in M4E1 lower.
what if i want to run a rifle lenght berral gas tube can i use a carbine length stock/ buffer system? or a rifle lenght stock and buffer with a carbine length berral and gas tube?
Many different combos can be ran. I would suggest trying it out, and testing a bunch!
This is very informative for a novice.. but it didn’t provide the information I was looking for.. it just stated the obvious to me .. I’m looking to find what advantages between them.. because on a 10.5 barrel (SBR) you can run pistol or carbine gas tubes..
And my gas block is listed in your list.. I have a .875 on my barrel..
I’m building a 16 inch mid length .750 adjustable gas set up with a rifle A2 buffer/stock kit. Would you think it will function with that set up, or would it need a carbine buffer set up?
Will work fine. Start from almost closed on the gas block. Open it a click at a time until you are loading without need for assistance and ejecting between 3:00 and 4:30. That's 90 degrees to just in front of your shoulder.
Then load your magazine with 1 round 10 times and make sure the bolt will hold open after that last round repeatedly. Call it a day.
Good video.
I always heard that the type of buffer is determined by the stock, NOT the barrel length and gas setup. I remember the popular 16-inch ARs back in 2000-2010 from Bushmaster, RRA and others that came with A2 stocks and ran fine. I currently have several 16-inch uppers with either carbine or middy gas systems. I run both on lowers with A2 stocks, mostly because I'm not a fan of collapsing stocks.
Is that a problem?
Thanks.
A2 stocks use the longer rifle length buffer tubes and buffers. It can be a considerably better / smoother tune if the rifle can utilize it. If you ever get the chance. Fire a 20" barreled rifle length gas system and buffer set-up next to any 16" or shorter carbine set up. The experience is completely different.
Buffer weight counters gas pressure. Gas pressure is affected by ammo, gas port length, and gas port diameter. And more buffer weight (to some degree) is more reliable for putting the next round into the chamber. This can be overdone though resulting in bolt short stroking. Basically. You are doing it right when your shell extracts between 3:00 and 4:30. Never forward, and never too far back.
@@bradharrison2411 20-inchers have always been my favorite AR15s. They are smooth, reliable and accurate. 😉
I want to build a 20" rifle length gas tube AR 15 but with a carbine buffer tube and spring, also utilizing a WOT trigger (forced reset) which recommends an H2 buffer for most standard AR 15's. Would I get better functionality from a different buffer than the stock carbine buffer weight because the rifle length gas system mitigates the need for an H2 or would I need an H2 or even an H1?
i have wilson combat 16 inch barrel intermediate length gas tube 13.25 what buffer tube do you think
Good presentation , I learned alot , took notes , I had an armorer ,gun store owner help me build my rifle chambered 5.56 -.223 (both) I chose a stainless steel 20 inch Barrell , after watching your video , I am concerned he ordered my parts , surely he installed the correct gas block size and tube , he is currently deployed on border patrol with government left good employees running store , I guess I should take apart measure , have not shot it yet . Be cool to see video showing how to exactly measure , I am a bit of novice still learning , I built rifle to hit pie pans at 400 yards I installed SIG Sauer tango 4 1x4x24 bi pod as well gessele two stage trigger ,anyway good video .
Started out as promising information... But ultimately all the stuff is intuitive and common sense. What I would like covered is overgassing and undergassing. Will a rifle length gas system have a tendency to over gas or under gas? Also my simulation skills are reaching its limit when it comes to the porthole size. Will a larger porthole increase gas pressure to the bolt or decrease?
I was looking at a 16-in barrel from Criterion that has a rifle-length gas system. It has a .750 port. Edit: this is barrel diameter, not port size.
I just want a soft shooting rifle that cycles reliably suppressed and unsuppressed. I just don't know what to pick.
I’m looking at a 16” rifle I really like but it says it has a mid length gas system. I was sort of hoping to hear if that is good or bad or just why a gun company would choose one over the other. My understanding is the longer the better in terms of ballistics and low recoil but I could be wrong. Anyway, nothing that answered my question in this video.
@@williamhicks2763 I ended up with a Criterion 16" midlength. Once a barrel is 18" or more, the better length is rifle length. It has to do with dwell time. Companies went for carbine lengths because a proportion of consumers bought cheap ammo that would produce lower pressures, leading to failures. The carbine and pistol lengths have higher pressures than the longer gas system lengths, and thus are more reliable with a wider range of ammo. Also, overgassing(higher pressure) does tend to wear on parts so thus the higher probability of buying more parts.
What if you don’t know what the gas port size on your barrel?
So ar 15 , 20" barrel with rifle length gas tube. Can I run a carbine buffer tube with ??........
So If I understood this correctly, Ideally, I'd need a rifle length gas system for a 24" barrel?
for me, this concept sounds a lot like intake pressure wave turning from the car space.
Hey I have a diamond back 7.62x39 ar pistol 7.5 barrel with a pistol length gas block . and want to buy a 10.5 barrel with a pistol length gas block will it work ?
What size gas tube would you recommend for a 16 in barrel?
95% of all 16" barrels use a carbine or mid length gas system. You have to figure out which one your barrel has. This will help --> truenortharms.com/ar15_default_store_view/blog/post/guide-to-ar-15-handguard-lengths-gas-block-position-and-muzzle-device-position
thank you
Thanks for the video, but it’d better if you could also explain the purpose of each part
I disagree with the correlation between gas system and buffer system. Other than telling people a barrel with a rifle length gas system will look silly with a pistol length buffer system. Also the bolt is moving the same distance when it’s cycling no matter what buffer system you have so if you are having gas issues you will need to properly tune the recoil system. If you need to adjust the tuning of your buffer system with a different spring or a different buffer weight a carbine buffer system will have the most options and available parts. But otherwise good video with very detailed information.
Agree ! I use same lower with different uppers , I may change the buffer weights !
Boss give me idea. How to set my 7.5 barrel. Its jam always.. please help me
Switch to a 10.5 with a carbine length gas setup.
Why do some companies make 16 inch carbine length rifles when mid length is better? Thanks
Yo I hav a 12inch hand guard would u use mid length gas system or carbine 9.75inch gas system because I currently hav a mid length 11.75inch gas tube does it need to be carbine length ?? Plz help
Depends on the barrel length. You could do a 12.5, 13.7, 14.5, or 16 inch and those are usually mid length gas.
@@midwestgunworks barrel length would be 12.5 inch I hav just purchased a 9.75inch gas tube aswell I will c what works best thank you for your help much appreciate this is my first AR bulid more of an AK guy to be honest lol
I hav been on AR forums most people recommend carbine length has tube for a 12.5 inch barrel
So a 20 in barrel with a rifle length gas system you can use a 5 ounce buffer and a rifle length spring, it will work with a six position stock. I'm new to AR platform.
Yes it should! Every setup is different so make sure to try it out and test for reliability.
I have 20inch barrel as well ,hoping my armorer installed right one , haven't shot yet .
Not true, length of gas system has very little to do with length of buffer, spring, or buffer tube, you can reliably run a rifle length gas tube system and run a carbine buffer tube, spring, and buffer, the military does this as well.
I'm only here to figure out how the hell my gas tube that is on top of the star chamber broke off from the receiver
Didn't really explain how it worked
I've built close to 20 ARs now over the years, and EVERY time I do an 18'' with mid length gas, and carbine extension tube and buffer (from different manufactures), I always run into the same issue. It does not cycle properly, doesn't hold bolt open when testing with 1 round in mag 50% of the time. I've used 3 different solutions. (1) Lighter buffer. (2) Softer spring. or (3) cut 1 ring at a time, then test fire, until bolt holds open, from the current carbine spring until reliably cycles (cheapest and fastest option)
You just came REAL Close to answering a question I had concerning gas systems.
Considering putting together a PSA, PA10.
On sale is a Complete lower with a Carbine Length buffer assembly.
Also on sale is a Complete upper, 20" barrel with a Rifle Length gas system.
So,"I'm" guessing this Won't work properly.
Think I better just stick with buying an 18" barrel kit that's set up as mid length.
@Mark Norwood I've only done AR15s, I don't have experience in the AR10 field. The problem I've ran into with AR15sbis that the mid-length gas system sends less gas to the bolt and thus the need for a cycling solution. With the AR10, shooting. 308, this may or may not be an issue, considering the .308 has a lot more gas. You need to ask the AR10 guys
The video is in 4k but why the intro in 720p? lol
👍👍👍👍👍👍👍👍👍👍👍👍
🇺🇦👍
This did not explain anything at all. An explanation would explain why would you want a carbine or a mid-length or a full rifle size. How about explaining the differences in length but use why would I want a carbine or why would I want a full length system
That was worthless
Just fyi but a lot of this information isn’t true
What isn't true? I'm pretty new to the ar system and don't know much of anything about gas systems
@@DirtyDirtbath
Sorry, just re-watching. Long story short, you are not gas:buffer system restrained.
There are systems that run carbine buffers with an intermediate gas
you can run rifle buffer system, OR A5 system on a carbine, intermediate, or rifle gas
you simply need to marry up th spring weight with carbine weight. You aren't exclusively tied to a specific buffer system because of your gas length.
With large frame guns in .308 or 6.5creed it's typically the same, but you tend to go way heavier on buffer weight
@tylerfrogley1227 excellent information, I appreciate it! Ive been looking at the a5 system
myth....
Lower those eyebrows bro
I’m considering buying a .300 blackout upper with a 16in barrel…the brand I’m looking at offers either a pistol length or carbine length gas system for the 16in barrel upper…which would be better? I’m not interested in suppressed shooting…I will shoot any grain…doesn’t matter about that bc suppressed doesn’t interest me
Thank you!
So I just built a new ar and wanted a robust hard use build and I always was interested in the ris 2 I used not cloning really but the m4a1 but I saw centurion arms made a Cold hammer forged chrome lined socom barrel with a tabbed and pinned gas block (don’t except leakage due to needing to shiny it back on per barrel but needing to go over you can partially pan from the factory so you can install but it’s that profile is that all the heavy barrel and with the carts for the m203 and its gas port being a carbine length m4 w more dwell time but harsher but w and h2 geissele buffer system .061 port size … they also as requested they polished the m4 feed ramps it is a hearty fucker w the optic setup a 1x8 and offset Red dot at 45 offset arisaka 35/45 degree mount sufefire dualfuel scout pro ds07 cloud defensive mount it’s heavy and gunna add more w a Troy mini broomstick if i can find one but .750 still I believe this has block it’s so tiny that a kid be how old and not so I don’t ask how tight it is it zigzagged the barrel on bottom and I like they tab and cross ok. The barrel that way it is good to go o. Full auto using the pinning and its easier to do yourself if u buy I believe the brd pinning jig and it comes w the bit and the last bit the taper reamer so the taper pin can be knocked thu but if unsure use a gunsmith people it’ll save u money until u know how to build a teir one gun it’s not only the price of what ur buying like upper barrel gas tube block ect it also is installing it secure/ safe/ accurate zeroing rail and barrel to optic ect but You can have the same parts built by two different people right next to each other and one will definitely outperform the other
I constantly build because every rifle I build is to my liking and I meant as far as gas ports go crane spec and not wide open or deal w adjustable only thing I do adjustable is the buffered system the super 42 but all of mine are in H2 configurations I am K 16 URG is 82 with a mid length system though MK4 10.3 dd barrel geissele mk 4 rail build radian lower also a n h2 and sharp 3-4 o clock using mk318 and mk252 smk and some other Speer 75 grain qualityity green tip all 3 have a 3-4 ejection and if it’s is spitting it off of the brass deflector at 1 o’clock you really need to have your buffer if you’re not running a suppressor while all that happens crane spec Gasport sizes need to less gas issues basically over gassing but with quality rifles are use quality and that’s key otherwise you’re gonna wonder why your Gucci rifle won’t shoot wolff or maybe the Winchester white box but for a green tip especially using it in the Marine Corps civilian green tip is very very different it’s not as powerful by any means military use like plus P they use better burning faster powders that are quality like M855a1 62gr Mk318 otm 62 grain and Mk262 otm 77gr much better performance and accuracy for sure and if u use full power mixed w reg range ammo the power of it u will feel dif so smaller ports but many don’t know what crane spec means