New Stag Arms Model 8 (Piston)

Stag Arms’s newest AR-15 is the piston operated Model 8 carbine.

Model 8 Piston Carbine

Stag have not released much information about the rifle. It looks much the same as their M4-style Model 3 carbine. I am not sure if the piston system is their own design (if you can identify, please do in the comments). It looks like it could be a long-stroke design, but I am not sure. UPDATE: See below.

Piston system can be seen when upper handguard is removed.
Caliber 5.56mm NATO
Upper Forged and Mil Spec
Operating System Short Stroke Piston
Sights Midwest Industries Front & Rear Flip Sight
Barrel 16″ Chrome Lined 1/9 Twist
Magazine Standard AR-15
Stock 6 Position Collapsible
MSRP (Price) $1,145 (standard model) and $1,175 (Model 8L left handed)
Availability December this year.

Lefties will be pleased to see that a left-handed model will be available.

UPDATE: David from Stag told me that it is a short-stroke piston that Stag Arms designed.

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • SpudGun

    And yet another AR manufacturer turns out a piston driven system. Looks like D.I. will be consigned to the history books.

    Is it me or is the gun industry getting as homogenous as the car industry – with everything looking and feeling and operating the same way but with a different badge on it?

    Why should I buy the Stag over the S&W or the Ruger?

  • The half-length piston tube and front-mounted gas plug look very much like an FN-FAL (late model; the early ones have a full-length tube.)

    -=[ Grant ]=-

  • James Martin

    I’m really hoping that they offer a retrofit kit for owners of existing Stag rifles. I have a Stag 2TL and would definitely buy a kit if it was offered.

  • James Martin

    This really looks very similar to the Adams Arms piston kit.

  • Jeff M

    I wonder how much just the upper half is.

  • jdun1911


    No DI is a better design then the Piston counterpart. It’s not going anywhere. The gun manufactures is cratering to people that don’t understand DI.

  • Lance

    From the looks of it its a close copy to the HK M-416 rifle.

  • jdun1911

    I don’t think it a close copy of HK or Adams Arms. It looks like an in house design. At least the gas block is pinned to the barrel.

    DI gun can get away with screw on gas block because they don’t have a piston hit it back and forth.

  • SpudGun

    jdun1911, you are an incredibly knowledgeable man and I always look out for you comments on here, but I’m going to disagree with you about D.I. going the way of the Dodo.

    I can’t think of a single new gas operated rifle that’s being designed or introduced with a direct impingment gas system. I do know that D.I. supporters love the accuracy and recoil of their gas systems, but the cleaning / lubing and perceived reliability of these weapons leave a lot of people cold.

    I believe this switchover is a direct result of AKs flooding the market and functioning almost flawlessly under extreme conditions. This maybe down to a piston gas system or more likely, the looser tolerances of the AK but the perception is that piston systems are more reliable.

    Unfortunately, the D.I. supporters always begin by saying ‘it’s just as reliable if it’s cleaned / lubed / maintained properly’. Also unfortunately, a lot of people don’t treat their weapons as well as you or I.

    Sorry, but I do think D.I. is on the way out.

  • Ken

    D.I.= Buh-Bye…Good riddance crud maker.

  • jdun1911

    DI has a piston too. AR DI doesn’t take much clearing to be honest. It just need to be well lube. That’s the key to any functional firearms.

    Pistol AR is fundamentally flaw. The AR was not design to take a piston. It was tried in the early 1970 and the flaws were apparent.

    1. It is heavier.
    2. It tilt, that means it will destroy your upper as well as your buffer tube.
    3. It has more parts that means more failures.
    4. It is less accurate.
    5. It has more recoil.
    6. It will not hold up in extreme weather especially in cold weather.
    7. When the piston jam it will be a hard jam. That means you have to take your rifle apart to clear it.
    8. It does not run cleaner. The carbon doesn’t disappear. It is redistributed to the piston instead of the bolt.

    I could go on but I’ll stop right there. This has been discus on AR15 as well as here.

  • jdun1911

    “AR DI doesn’t take much cleaning to be honest.” That’s what I meant.

  • Tom

    I won’t jump into the DI vs Piston debate (though I have extensive experience with both systems and working on them) but I will point to some interesting options when sticking with DI that can alleviate some of the issues people have with them.

    There’s been some advancement in metal coatings in the past few years which have a lot of promise in the AR department. I’m referencing specifically the FailZero brand, who coat bolts and bolt carriers (as well as 1911 slides and parts) in their proprietary “exo” coating which has a very slick surface and extremely long life. Their claims aren’t bogus, you really can run your AR without lube using their BCGs. If I recall Costa and the guys at Magpul ran a FailZero BCG through a couple courses and were very happy with it. Brownells carries them now, and they’re in the same price range as a good chromed BCG.

    For my (current) personal DI AR, I use a cleaner called Gunzilla which also doubles as an exceptional dry lubricant. Since I built this gun a few months ago I’ve used nothing but Gunzilla to clean it, including the bore, and the results have been overwhelmingly positive. I essentially scrub it down with Gunzilla, run a patch or two through the bore, and wipe down the BCG with a shop rag to mop up excess. Then it’s off to the range, no oiling or greasing of any kind. After a dozen trips to the range and a heck of a lot of ammo (both drills and bench shooting) I have yet to encounter a single malfunction of any kind.

    Anyway, anecdotal as it is that’s my two cents. Both work, both have problems.

  • Whatever

    The thing about the AR is always mentioned is that it needs maintenance, that if it fails it is due to the user not doing all that is necessary. For a hunting rifle I can understand that, but for a battle rifle that’s insane. I don’t ever remember hearing of GIs during WW2 having to do fastidious maintenance on their M1 Garands to keep them operating yet I do remember hearing how in places like Iwo Jima that taking a time out to clean your weapon was not possible or an insane thing to do.

    A battle rifle should be reliable above all else and the direct impingement of the AR is not even close to the most reliable design.

    As to the product at hand, I don’t get the reasoning behind making yet another AR, piston or otherwise as the market is saturated. Everybody makes an AR or a 1911 nowadays.

  • ctr

    cmmg gets no love?

  • Vitor

    And about accuracy…there are piston guns known for good accuracy, like the the SIG551 and the HK417.

  • jdun1911


    There will be always more pistol type rifles then DI. That’s a given. In term of volume the AR is second to AK.

    Did you get my email on the IAR? The Marine is going to decide who is the winner this month.

    I agree that Colt will be the winner. The company is run by an ex Marine General after all. hehehe


    There is no need for special coating. It’s just a marketing gimmick. The problem is people do not put enough oil on the rifle. I’ve seen posts that stated a drop of oil is all you need for X rifle. That is pure BS. You spray the rifle down until it is dripping oil. If you don’t like oil, use grease or whatever. The important thing is that firearms needs to be well lubricated.

    The AR15 needs to be “well maintenance” is BS. What AR and other rifles needs is lubricant. My AR that I use is heavily greased. I have over 2k 5.56 and over 10k of .22lr and the only cleaning since then is running a bore snake twice. The inside of my AR is full of filth, with the exception of misfire on .22lr ammo I have no malfunction.

  • jdun1911


    Piston in whatever form if all things are equal, DI will win 10 out of 10 times.

  • Tom


    I respectfully disagree regarding Failzero’s products. I’ve had some experience with their stuff; despite not owning one of their BCGs myself I do plan on purchasing one at some point. They’ve been very open to critique and have handed out demo units to a number of firearm industry bigwigs to test, including Costa and the guys at Magpul. I’ve heard nothing but positive feedback on them thus far.

    If a particular type of finish is more effective in preventing malfunctions, while at the same time requiring less maintenance on the user’s end, why not? Chromed BCGs and chrome lined barrels were once a “marketing gimmick” as well, and now they’re just another accepted part in the AR builder’s vast catalog.

    As I said, I’ve run a couple thousand rounds through my DI AR running it completely *dry* and only wiping the BCG off with a rag after a range trip. Gunzilla is another “gimmick” product that does really work, and saves me lots of time with the many clean an oil jobs I do a month at the shop.

  • Oakenheart

    Hm. Looks like the FailZero coating is the nickel-boron stuff from UCT. UCT picked up some DoD contracts to coat wear parts on existing arms too. Interesting.

    I’d love to try nickel silicon carbide coating on AR parts. The coating has a hardness rating of 600 on the Vickers scale, and a sliding hardness of 58 to 60 Rockwell C. It also has the ability attract and hold oil (“oleophilic”) which makes it very wear resistant. They use it in sleveless motorcycle engines as a cylinder bore coating. Wonder if a hybrid coating is possible, using nickel boron with silicon carbide… hard, holds oil, and has self lubricating properties. Coat all the moving stuff and the barrel too 🙂

  • This is just a pined in CMMG Piston retrofit kit. They just leased the patents from CMMG and had their name engraved on the bolt carrier. Not a big fan of the CMMG kit as I have heard a few problems with reliability. My AA kit seems to be working well and SW M&P series AR-15 rifles will have a pined version of the AA piston kit avaliable possibly by the end of this year.

  • Jin

    I own a POF. This is my first piston AR and so far i love the rifle. My only complaint is that my picanny rail is 12 inches long and it adds a ton of weight to my rifle.
    I fired a ton of M 16 A2’s, A4’s and M4’s and they all performed well. The only part that i hate about the gas operated systems is that it gets very dirty and cleaning the chamber becomes a pain. I found that for the battlefield the current M4’s and A4’s are not very reliable. You have to cake the rifle with oil and the oil attracts all kinds of dust and sand causing malfunctions.

    During ideal weather conditions, i believe the gas system will do just fine, but in the sand box or in the jungle i think the military could really benefit from a piston AR.

    As far as my POF goes, i read an article that i could fire up to 15k rounds without cleaning the rifle because the entire upper receiver, bcg, and charging handle is coated with their NP3 coating. With the price of ammo the way it is, i guess i will never find out.

  • technique

    That be a CMMG Piston, on yet another crappy Stag gun.

    Ya know what pistons are good for? Cans. They are still dirty (contrary to popular belief), but still manage to run cleaner (just slightly) in comparison to DI.

    I will still take a DI over a piston any day..The only piston system on the market that looks any good – and functions great, is the PWS system…stays true to AK form.

  • Erik

    True it is just the CMMG retrofit kit and due to the fact that it’s aluminum I’m not a fan. SW M&P model uppers have a few that used a pined version of the Adams Arms kit but is a decent grade Stainless Steel (410C). Essentually the Adams kit is a more user friendly version of the LWRCI and reliability is pretty much the same. Contrary to what some have writen in this blog STAG makes high quality rifles at a super low price. Most brands are a “get what you pay for” level of quality but not STAG. I have 2 DIs’ and 1 piston upper, 1 DI and 1 Piston in a Carbine length system and the other is a Rifle length DI system. All work very well although the Piston is much cleaner and cooler. My piston is on an 11.5″ with a ADDAX FSC 556 Brake and it works well. 1 DI is a 15.5″ with a Bushy AK-74 Brake on a Fluted Bull and the other is a non-comped 20″. CMMG makes good rifles but I don’t recomend their Pistons due to materials and horror stories. If you have the $ buy a POF, LWRCI, Spikes Tactical, Adams Arms, or a Osprey Kit as long as you’re using a 14.5″ or smaller barrel with a gas block diameter no larger than .750″. To each their own so don’t knock the Piston or the DI because each have their + and -.
    The SBR DUDE.

  • nonegiven

    I emailed stag about the comments that it is just a CMMG and they stated that it is NOT a CMMG. It is made in house, but they did say it looks similar. FWIW

  • John

    There are a lot of good points in DI vs Piston debate listed above. The one thing that dissapoints me about the SA Carbine is that they are not taking advantage of the Piston to allow the use of a folding stock. Anyway I will stick with my AK as it goes bang everytime without hi tech lubrication.

  • Charlie Brown

    DI vs Piston

    Enough already! Both have their Pros and Cons.

    The final decision lays with the owner or shooter. What works best for him or her, for what ever situation. I can’t tell you how many people I have seen at the range with high dollar AK’s and AR with marksman skills that have my 10 year old son laughing at.

    People, purchase something you like and are comfortable with. Above all, know your weapon inside and out. Practice, practice,practice. Have fun and enjoy.

  • Dwayne

    Back to this particular rifle, the Stag Arms M8, they say that they’ve modified the bold carrier to correct for carrier tilt. Sure, I would expect to see carrier tilt in a gun with a conversion kit, but not with a bold carrier designed to correct for it.

  • I have 3 Stags, a model 2T & 6 and the new model 8. I used the 2T for several years as a backup for my service weapon and even qualified with it every year flawlessly. The model 6 is my prairie dog gun. Both have been equal in quality to every m4 variant I’ve had the pleasure to operate. I also have a ZM Weapons piston rifle that has been in use on the borders of Texas for years with absolutley no issues. I’ve used these m4/ar/m16 types in all configurations by almost every manufacturer with no “real” problems. I have to rate the Stag as one of the best. I recently purchased the Stag model 8 and have cycled several hundred rounds thru it with no “probs” yet. Very impressive firearms.

  • zak

    I am a south paw and was planing on buy the stag L1. Then i read articals about speical forces switching to the hk m416 and how it performes better than the standerd army issue m4. After that i thought about the stag m8.. dont know what one ill end up with but they both seem to be very good.

  • John Doe

    I’ve never fired a piston AR-15 but I am looking into buying this model sometime in April. I think it offers a huge advantage over D.I. simply because it runs cleaner and thus is more reliable. Our SWAT team uses D.I. M-4s and we had a lot of problems with jams in the beginning until we fixed the problem by cleaning our weapons every single time after we went to the range, which of course is a little bit of an inconvenience. I’ve never had my M4 jam on me since then, so they are very reliable weapons IF cleaned/lubed properly. In law enforcement/civilian use this is not a big deal, but like a few of the others mentioned, in warfare I can see how it is a big disadvantage. Ive met several soldiers that were deployed in Iraq and Afghanistan and all that theyve said of the M4 is that it’s a horrible weapon because of all the reliability issues. I would like to see a model like this tested in those scenarios to see how it would perform.

  • BWall

    Bought a CMMG piston gun few months back. I was surprised when I saw the Stag. It’s not just similar, it looks EXACTLY the same.

  • Ironsmurf

    I’ve been torturing myself over which AR to buy, and what I’ve found through all my research is that if you take care of your weapon, you won’t have issues.

    Let me qualify this by giving my history: I’ve been in the army for 6 years, two tours in Iraq. The only problems I have ever had with my service rifles were from junk magazines failing to feed properly. I have never had another issue. That said, I always cleaned my rifle before I ate (priorities!). I was disgusted by John Doe’s statement (no offense) that his SWAT team was “inconvenienced” by having to clean their rifles after every time they went to the range. Isn’t that your job? What craftsman doesn’t take good care of his tools?

    I hate cleaning up after a DI gun, but it doesn’t take very long and it’s quite a bit lighter than the piston models I’ve held.

    I’m heading to the store to buy a carbine this morning, and I’m still not sure which I’ll buy. I went there yesterday and found two likely candidates, one was the Stag M8 and the other was a S&W M&P DI carbine.

    Here’s my bottom line: who cares what system you get? If you don’t take care of your babies, how can you possibly expect them to treat you well when they grow old?

  • Ironsmurf

    FWIW, I went with the DI gun. I figured that since I’m already familiar with it, and since it was cheaper, what’s to lose?

  • KeithB

    I bought both stag 3 and 8, best of both worlds, i am pretty sure the piston and rod are stainless steel, both awesome ARs.

  • Rick

    Just got my stag model 8 this morning. fired several round through it, love it so far. Took me 2 months worth or researching to find out bout them. big seller for me was the lifetime warranty they have. Overall a lil more recoil than a DI model, but love it nonetheless.

  • joe c

    i have been looking at the model 8, i found one for 1,199.00 brand new, softcase and 10 round and 30 round mag. is this price okay?

  • Ironsmurf

    I might keep looking. I found one lightly used for 850 in Indiana.

  • KeithB

    I sell them brand new in my store for $1025

    • Mike

      I was wondering if you still have anymore of those stag m8s available to sell? I am looking to buy. If you can please e-mail me and let me know how many more you have in stock.

  • joe c


    can i get your phone number or website, so i can contact you

  • KeithB

    Joe, are you in NY? my email is

  • Bob Duke

    I have a Stag Arms M-8 and I seem to be having a blown primer problem. I don’t know whether it’s the rifle or ammo. I used Selior & Belot 55gr fmj .223 and I’ve had primers blow and drop into the Trigger Housing Group and lock up the rifle.

    I’m wondering if it’s the ammo. If anyone out there has any info or guidance please contact me


  • rj

    hey spud gun,if oyu knew anything about the s&w ar,you would know that they are made by stag arms and have been for a long time! they just put a nice m&p brand on it so they can charge you more.(stag has lowest price gas piston ar’s.) thats one reason to buy stag over s&w.

  • sbrdude1

    Actually you’re wrong on the manufacturer rj, it is an Adams Arms design with a few small modifications per S&Ws direction. Stag makes good piston guns but S&W’s are a better more robust design hence the higher price.

  • Rick

    For what its worth, I have owned a Model 8 for 8 months now. After close to 3000 rounds through it (and killing my wallet) I have had NO jams or malfunctions.
    Despite what people say about oil, I have found Rem oil (or other dry style lubes) works best on the bolt, and I use some CLP on the charging handle (upgraded to Vltor BCM med latch).
    I use Hoppes and a hoppes bore snake for the barrel and piston.
    I only lube the piston, and leave the rod dry (collects less dirt and have seen no abrasion) with rem oil.

    I found most 5.56 and .223 function similarly and have similar dirt. I prefer using Remington .223 UMC (more accurate), BUT it seems to create more heat than AR223 from AE at the piston block.

    Its more than accurate enough at 100 yrds (biggest range near me) and super easy to clean.

    The bolt simply needs a quick wipe (sometimes a wipe of the firing pin and spring) and it goes back almost as clean as new.
    The piston takes more work, but its easier than dealing with gas rings, etc.

    It takes all accessories (Magpul, Vltor, etc.) as well

    Its the best Bang for Buck piston system out there. IMO.

    I clean the entire rifle after every shooting session (150-300 rnds per session) and only lube it when i clean it. It has sat for weeks and come out dry, fires 100% perfect.

    my ONLY gripe is that I did not know there was an upgrade package that gave you a better twist rate barrel. I should have gotten that.

  • Viper6

    Well I own this Model 8 and loved it the first day when I put a solid 500rds through it with no FTE’s. After a complete strip down and cleaning (to include the piston) and reassemble, and lube it was locked away for about a month. This past weekend I took it out again with another can of 500rds in hopes of dialing in some new accessories. I am sad to say that it had an FTE the very first round. I pulled the charging handle, cleared the lodged brass, chambered a new round and fired again……FTE…..repeated the previous process and yet again FTE only this time it split the bullet casing in HALF!!!! So of course I ceased fired and field stripped the weapon and double checked the functionality of components and reassembled the rifle and performed a functions check. Another FTE…..I tried 3 types of ammo (remington 55gr, Hornady 55gr and federal 55gr) and 6 different mags. I am trying to find anything written about Pistons jamming and not finding anything. Any ideas or suggestions? I know there isnt much to go on.

    • Trevor

      Are you sure you didnt turn of the gas system/piston by accident? Because you can turn that thing on and off right up there by the lug…

  • WackoWoodchuck

    I stop in at my usual gun store and there was Stag AR Model 8. Have been looking for a AR as I have had a Mini-14 for some 30 years. Which never jammed once in 5,000 – 10,000 rounds. As soon as I saw this AR I looked down the sights and it just gave me that felling u know!! it had to be mine and I look around and there was no other guns in the store. Gun show in down, anyway Stag and piston driven was knew to me but I walked out within 30 min. Love it and out of all the other AR’s you can’t beat it. ( Added a EOTech holographic XPS2-2 sight butted up with 3x EO scope, you will have one nice AR)

  • Viper6

    @ Trevor. Somehow I never saw your reply. The same day I posted I found that ther indeed was an on/off for detent on the gas block screw. Why in the world is this even an option? I understand having a variable one to increase or decrease the amount of gas if you want it suppressed. I do not see any logical reason for turning it off. After learning about the minute turn of the gas block screw from one detent to the other this rifle has been amazing and fired flawlessly again. So once again it was “operator” error.