The debate has raged for years: AR-15 or AK-47. Precision or reliability, direct impingement (DI) or piston, 5.56 NATO or .223 Remington. Usually the process of choosing a “perfect” rifle for competition, self defense or even hunting is filled with compromises that need to be weighed in order to determine which tool fits the job best. But not with PWS’s line of rifles . . .
The AR-15 market is about as diverse as a redhead convention in Finland. Some might use a different bolt carrier here or a new handguard system there, but very few actually offer legitimate “improvements” over the basic design that Eugene Stoner came up with more than 50 years ago. The PWS MK 114, however, features one very legitimate improvement that puts their rifle ahead of the competition: the operating system.
There are an ever increasing number of AR-15 rifles on the market that use a gas-piston system instead of the traditional gas-expansion/direct-impingement arrangement that Stoner designed, but almost all of them, from Adams Arms to LWRC, use a short-stroke piston instead of a long-stroke piston system. The piston guns’short-stroke method means the operating rod only acts on the bolt carrier for a short period of time and imparts all of the force on a small strike face at the top of the bolt carrier (where the gas key usually is).
The problem is that the AR-15 was designed to have all the force in the bolt carrier centered, with the bolt acting like a gas piston itself and keeping all of the forces roughly in-line with the direction of travel. By having the force applied off center in this way, the bolt has a significant amount of “carrier tilt” where the back of the bolt carrier will constantly be rubbing against the bottom of the buffer tube. It’s not ideal, and over time it can lead to excessive wear on your gun.
The beauty of the PWS design is that it’s a long-stroke system, meaning that the long piston is directly attached to the bolt carrier group and extends all the way to the gas block. The longer piston means that the rotational force applied to the bolt carrier is significantly reduced, and as a result there’s almost no carrier tilt. The gas tube along the barrel provides a guide for the piston and keeps everything straight as the gun cycles — exactly the same as the piston system in the AK-47.
In order to make the gas system work with standard charging handles, Primary Weapon Systems designed the operating rod to be segmented instead of a single solid rod. The front section is slotted onto the bolt carrier, and can be detached to slide the charging handle of your choice onto the bolt carrier assembly before inserting the whole thing into the receiver. It’s a touch more difficult than the normal AR-15 reassembly process, but it’s very straightforward.
One of the side benefits of a piston system like PWS uses is that you also get an adjustable gas port. Normally in an AR-15 the gas expansion system is self regulating (to a point) and will continue to function even with inconsistent ammunition. But with the PWS gas system, you can adjust the amount of gas being bled off from the barrel and tune the system so that you have just enough energy to cycle the action. A properly tuned gas system means less excess energy being transmitted to the shooter, and therefore less felt recoil. Add in the extra reciprocating mass of the piston and the rifle gets very gentle.
Adjustable gas block systems also mean that you can get improved reliability in those situations where the shooter’s comfort is a secondary concern — like a battlefield. If you’re in a dirty environment, you can turn up the gas system and more energy will be siphoned off from the gasses in the barrel, leading to faster cycle times and better reliability. You don’t even need to whip out the tool kit to make that change: the tip of a 5.56 caliber bullet will let you make the adjustment just fine.
PWS could have stopped with the improved operating system and called it a day. It’s the best piston system available on the market, and might even have given Stoner a moment of pause if he’d seen it. Instead they decided to kit out the gun with some custom parts that use some of the best technology available.
First up is the most noticeable original part: the muzzle brake. PWS’ FSC556 is one of the best there is, and as a result it’s used on many manufacturers’ guns, not just PWS’s. FNH USA, for example, chose that muzzle brake for their SCAR series of rifles. The reason is pretty clear when you get the gun on the range, as it’s an efficient design that works really well.
Another improvement is the buffer tube (or “receiver extension tube” for you semantic pedants). PWS uses their own CNC machined buffer tube that doesn’t need a castle nut (and so won’t walk itself out of position), has some QD mounts built in for added convenience, and has an extra lip on the front that helps eliminate what little carrier tilt is left. The original design for the collapsible stock on an AR-15 was a hastily designed disaster, and PWS’ solution is one of the first that actually feels like someone sat down and thought about the problem for more than five minutes.
The last improvement is in the rail system. PWS uses a free floating barrel to improve accuracy and keep the handguards from heating up, which uses a full-length top Picatinny rail and a keymod attachment system that has become extremely popular lately for everything else. That allows the shooter to either attach individual rail sections where they need them or simply slot attachments directly into the keymod system, keeping the rest of the handguard flat and comfortable.
It also cuts down on weight and makes the rifle much more comfortable to shoot while giving up exactly nothing in terms of configuration. All of the high-end manufacturers from Accuracy International to Knight’s Armament have switched over to this system, and I expect it to be the industry standard for “tactical” AR-15 rifles in the next couple years.
Whatever parts PWS doesn’t manufacture, they source the top shelf versions available. Instead of a chintzy standard charging handle PWS uses the BCM Gunfighter charging handle. Instead of the standard spongy trigger is a QMS Mil Spec trigger, which I reviewed and use in my 300 BLK rifle. And for the iron sights, stock, and grip, PWS decided to run with the Magpul versions. In short, it’s a rifle kitted out exactly how I would kit out a “run-and-gun” rifle.
Out on the range, the gun performs superbly. It’s a dream to shoot, lightweight enough to transition smoothly from one target to the next while being solid enough to build bridges out of. Everything on the gun felt “right.” But before I passed judgment, there was one more test to complete: accuracy testing.
PWS custom machines their own barrels from blanks, and this barrel was no different. They use a 1:8 twist, imparted using a button rifling process (not the most accurate process, but good enough). The chamber for the .223 caliber projectiles is the increasingly popular .223 Wylde chamber, which combines the best features of the 5.56 NATO spec and .223 Remington to accommodate both types of ammunition while maintaining the best accuracy. And on the 100-yard range, it certainly looks like all that work paid off.
This five-round group was shot using bog-standard 55-grain Federal American Eagle .223 Remington ammunition, also known as “the cheap stuff.” But even though the ammo wasn’t the greatest, the rifle performed remarkably well. The horizontal dispersion of the group was about 1/2 inch center to center, and vertically the shot group was about 1 inch center to center. I went back and re-tested with some nice Winchester 55-grain ammunition and started getting bored with the 1/2 MoA groups I was getting with the rifle. I’d post a picture of those instead, but I think this group using the most common ammunition available is more impressive.
There is a small caveat: The gun didn’t like 77-grain ammunition for some reason. I think that the twist rate might not have been ideal for the heavier rounds, and I couldn’t get a good group with even match grade Federal Premium ammunition in that weight.
There are very few rifles that I actually like. PWS’s MK114 rifle is definitely one of them.
Specifications: PWS (Primary Weapons Systems) MK114 Rifle
Chamber: .223 Wylde
Barrel Length: 14.5 inches (pinned and welded flash hider)
Weight: 6 pounds, 9 ounces
Capacity: 30-round magazine
Features: PWS long-stroke piston operating system, three-setting adjustable gas system, forged upper receiver and lower receiver, included forward assist, FSC556 compensator, MLOK free-float handguard, 1:8 barrel twist rate, Bravo Company furniture, Radian Raptor Charging Handle, does not require NFA SBR paperwork, minimum recoil impulse, good for law enforcement, hunters, competition shooters, as well as everyday firearm users
RATINGS (out of five stars):
All ratings are relative compared to the other weapons in the gun’s category. Overall rating is not mathematically derived from the previous component ratings and encompasses all aspects of the firearm including those not discussed.
Accuracy: * * * *
1 MoA with standard 5.56 ammunition is nothing to sneeze at. 1/2 MoA with better ammo is excellent. But the lackluster performance with heavier bullet weights was disappointing.
Ergonomics: * * * * *
The rifle feels exactly how an AR-15 should.
Customization: * * * *
PWS rifles give you tons of options on how you want to set them up, from keymod attachments to QD cups and everything in between. But the long-stroke gas system limits your options when it comes to replacement bolt carriers.
Overall Rating: * * * * *
I honestly can’t remember the last time I gave anything a five-star review. But this rifle absolutely deserves every single star. A nicer trigger would be a welcome addition, but it works well as-is.
More from The Truth About Guns:
PWS Updates Their Mk1 Rifles to Mk1 MOD 2
Choosing a Competition Rifle: SCAR 16S versus PWS Mk114
I understand bolt carrier selection, but I was under the impression PWS uses a standard bolt?
Big fan of their rifles, and their TFL vid (FUUUUUUUUU**YEEEAAAAAH!) and most of their other vids. Half-cocked…not so much.
Half cocked is a resounding dud! From my perspective anyway.
I’m a long stroke guy all the way…pun intended.
U are saying u are almost a vegetable?? 😀
Really? Another AR? Do somthing different, like an ak or an m1 carbine, lest this be the truth about ARs
2k? I guess out the box top tier AR it’s not totally horrible price but I just don’t get out of the box AR’s as one can build a AR specifically for their needs and unless there is some $500 stripped lower I don’t know about I’m not sure what the extra added price tag is for. Basic stock, magpul sights are basic quality, a basic muzzle brake which is toted as “one of the best there is” never saw a need for one, a free float barrel with basic handguard with rails, and we all know the “long stroke” system is a gimmick.
$1,500 AR marketed to 2k.
I love AR’s, I love new tech, I love new designs but the ONLY thing different with this AR is the long stroke. So what?
I was under the impression that 1:7 was best for the heavier bullets (75gr +). Perhaps 1:8 isn’t enough to sufficiently stabilize the 77gr bullets you tried.
That is my understanding. The latest trend, however, is the selection of a happy middle ground for a barrel twist. Unless you grow your own, MK 262 (77 gr) and other heavy gr. match ammo is spendy. In most scenarios, the average range fodder in 55, 62 and mixed varmint loads in the 40s are used, so many AR mfrs. are choosing 1:8 for better all around use.
I’ve never had any accuracy issues with 77gr pills in my 1:8 twist M&P-15. In fact, it seems to do better with the heavier bullets at >100 yards. Huh.
AR’s were soooo last school masacre !!
Are you trolling?
No I do not troll…just think if you have seen one AR you have seen them all…its not my thing, I’m a pistol guy. And yes maybe I have a sick sense of humor lol
Don’t let these crybabies discourage you, Jon. Keep on with your sick demented humor! It keeps people on the alert.
I too found that to be in poor taste. I’m with you on the AR boredom, but surely there’s a more tactful, less offensive but also humorous way to say it?
My humor is not for everyone….
I think alot of inflection is lost when using written word instead of speaking so I can see where you’re coming from, but perhaps in the future using a /sarc note would be worthwhile. Otherwise we might think you were weird or something. Anyway, no real harm done, it is just an internet post.
I agree some things can be lost with the use of written word. Noted about using a sarc note.
Not gonna lie, that made me laugh
I also giggled a bit at it.. but yes, it was over the top.
I should also confess, I found it funny.
Just use /sarc tags so people don’t misunderstand. I lost count of how many people were/are angry at me because they don’t know I was joking.
Oh you tricked us. You made us think it was the mag on FB.
You could find some of the pws rifles for $1600 late last year on certain websites if you…AIMed hard enough.
If I were to own an AR it would be this (+ the Ironwood wooden stock set).
Piston system seems fine, but carrier tilt has been a thing of the past for a couple years now with better designed BCGs.
That piston is considerably longer than the one in the HK 416/556. Interesting.
Depends how you define piston. The first piston head is probably the only part you can really call a piston, and the piston head is possibly smaller than the piston on the 416(if you don’t include the area that exists only to hold the op rod).
Nice rifle. I’d love to get into the piston game. However, since the cost of entry is so high I’m going to have to wait. Hopefully prices come down in the near future, I need some reciprocating mass to help tame the massive 5.56 recoil, otherwise my shoulder is surely doomed.
Definitely. My Buffalo Bore .45-70 +P and Lightfield 12 gauge slugs aren’t half bad, but 62 grains at 2950 FPS will definitely mess me up. /s
Seriously, though, 3 gunners and other competition shooters like trick muzzle brakes and ports in order to help slim down the split times.
Zero carrier tilt problems on this owners LWRC M6 SPR, even after thousands of rounds.
LWRC and Sig have essentially eliminated the carrier tilt issue by way of custom BCGs that are flared at the rear, precluding them from having any room to tilt.
They also machine the piston strike plate and BCG from the same billet, eliminating the “modified gas key problem”.
Other manufacturers may do this as well, but really it should be the standard for piston ARs.
I’d love see it compared to B.E.A.R. Elite. Review anytime soon?
Actually just about to email their PR guy to get one to review. Stay tuned.
Comparsion of Internet’s two “Best ARs of all time”? This is gonna be legend – wait for it – ARy 😀
What about Larue?
I am not in the AR game so I don’t know much.
My money’s on B.E.A.R.. It’s accurate as hell and the piston system is simple and efficient. And works flawlessly even with MAG5-60 which is really an achievement
I own a PWS mark 114 and used to own an ADCOR B.E.A.R. Elite but I sold the Adcor because it was an inferior weapon with problems and when I contacted the company about the issues I was having with my Brand new rifle they just blew me off and said tough luck !!! The B.E.A.R. is a little softer shooting than the PWS but it is also a few ounces heavier and the weight is mostly towards the front of the rifle making it feel a bit front heavy and unbalanced in the hand, also when I put my vertical grip on the bottom rail attachment the vertical grip would constantly rattle and move a little bit because the lower rail attachment is not designed to be completely tight against the other parts of the free floated barrel, my guess is that its this way so that you can remove the lower rail attachment easier if you need to get to the barrel for maintenance or cleaning? overall the PWS is more ergonomic, better balanced and lighter Oh and it was More accurate on paper targets as well…the Only thing I liked about the B.E.A.R. when I had it last year was that no one at my range had it !!! Lol 🙂
Hi, I had an ADCOR B.E.A.R. Elite that I bought brand New last year and I Did compare it to my PWS Mark 116 since they both had 16 inch barrels and your Not going to like what I discovered about the B.E.A.R. and Adcor who Dont stand behind there products namely its owner and president Mike Brown and his resident Flunky Dayson Broadwater. I fired 60 rounds of federal 556 55 grain brass cased ammo thru the B.E.A.R. when the trigger started malfunctioning to the point where it would NOT fire any more 🙁 I clreared the weapon multiple times and took out the bolt carrier and inspected it at the location where I was shooting and could Not see any physical breakages or malformations so I put the weapon back together and it still would Not fire! I e-mailed Mike Brown about the faulty trigger and he said he would fix it for me and would be sending me a return addressed Fed-ex rifle box to my home adress shortly, well I figured that since he was going to be paying for shipping of the rifle from my home to his business and back, it would cost around $50 for an oversized item, so I asked Mike a few days later if I could please just have a pair of Magpul plastic M-bus sights which retail $ 90 at the time and I Would just buy a new geisselle trigger and have my gunsmith install it and Mike said Yes that Would be Fine instead of him having to ship the rifle to his business and back to me after the repair which would cost almost the same as the Mbus sights! Well in between the e-mail correspondence between myself and Mike Brown one of his low level Flunkies by the name of Dayson Broadwater got wind of the deal me and Mike made and told Mike not to follow thru w/ it so a few days after Mike agreed to the deal, He renegged on the deal and I was Disgusted by Dishonesty and Awfull rifle anyways so I sold it quickly, The Bad of the B.E.A.R. 1.) when you attach a vertical grip to the lower section cuz the handguards get Very Hot after 50 rnds it is always a bit Loose and Rattles cuz of the propriatery lower design which can be removed which is Very hard to do and takes Forever(another poor design) 2.) the rifle is Very front heavy 3.) Poor accuracy even with the 16 inch FN cold hammer forged barrel 3.) piston design is difficult to understand and did Not come w/ instructions on how to operate it! I had to e-mail Adcor customer service twice to get them to understand there arent clear points of reference on there Poor piston design! Want a MUCH Better Rifle W/ Great Ergonomics and that Doesnt rattle when you put a vertical grip on it and is Much lighter and Better Balanced and Not front heavy and a Company that has Excellent customer service then go with PWS !!! I Have bought a PWS Mark 116, Mark 114, Mark 116 7.62 x39 upper, Mark 116 300 blackout upper and Not had any malfunctions in ANY of them whatso ever !!! Cant say the same for Adcor
I am a big PWS fan, and I own two Mk114’s – both an older Mod 0 and a current Mod 1 as shown in this review. They are both fantastic rifles – accurate, reliable, and LIGHT. The new Mk114’s are 6.5 pounds. I bought my first one to replace my Robinson XCR – a beautiful gun, but pooor factory support and HEAVY – 8.5 pounds before putting a scope on it. I bought my first Mk114 for $1600 and never looked back. Are there cheaper options? Sure. But make no mistake, this is a top tier rifle, and it is worth the price.
Remember, the price you are looking at is MSRP – street price will generally be about $300 less.
I had an AR-like rifle with a long-stroke piston system. It shot very accurately, although the gun was pretty heavy. Side folding stock, AR-like ergos, AK-like functionality.
Daewoo K-2. Picked mine up in 1991 or so, NIB for $279. Wish I’d bought a boatload of them at that price.
Why does it seem like every guy who ever had a Daewoo rifle sold it at some point? That’s one I never would’ve let go.
Call me when they bring back the 7.62×39 Uppers.
Two AR rifle reviews in two days. Think maybe Nick is arming up for the coming “troubles”?
What shocks me most about these rifles is the cost–with everyone and his brother churning these things out as fast as they can, and all the parts being pretty much the same as any other part, aside from triggers and barrels, you’d think the cost would have to come down. And it’s not like it takes any great skill to put one together. then there is this whole piston game. AKs are made the world around, so there is nothing magical about building a piston system, and there are only a few extra parts. To me, it looks like they are charging 2Gs for an $800 rifle.
Maybe they increase price to reduce demand? That way they avoid getting swamped by too many orders.
I’m incredibly disappointed that neither the redhead nor the Finland link actually linked to a Finnish redhead competition. Or any Finnish competition involving women for that matter.
I was also bummed out. I was hoping they reinstated the “links to pictures of goid looking women” policy.
Could we get a good picture of the receiver extension to go along with the compliments for it?
Looks like a great gun, but I don’t know if I could justify 2 grand for it. Maybe one day when I’m not a poor college student saving up for a chi-com SKS.
Here is a link to a video PWS just put up today – it explains all the features including the Enhanced Receiver Extension:
What about the lightweight profile barrel? Sure it’s great for being lightweight, but it affects accuracy during strings of fire. I want to see accuracy testing done as the barrel warms up. Fire a mag or two through it, then quickly do a 5-10 shot group with it to determine accuracy and POI shift.
Thanks Nick, great review. Looking forward to the comparison.
PS: there are OTHER writers reviewing other guns, guys- give Joe Grine and Chris and others some love and maybe they can bring out some bolt guns or something else interesting.
Or you could always do your own?
Piston ARs have been around forever.
I don’t get it. A short stroke piston hits what used to be a gas key for a short period of time with enough force and the bolt carrier goes back on its merry way. Isn’t this the same thing that direct impingement does force wise? Seems to me like the same thing, just a lot cleaner.
It isn’t quite the same. In a DI gun the gas travels THROUGH the gas key and expands inside the BCG, pushing rearward against the carrier and forward against the bolt at the same time.
I own one and love it to death. Got it for $1,550 and consider myself very lucky but you can find some on Gunbroker for about $1.6K. I was waiting for a review to see how TTAG felt and glad I made the right choice. 🙂 Although, I didn’t know 77gr bullets had that effect as I’ve been shooting mostly M193 so I gotta try that later whenever I get more funds.
Also have a MK114 Mod 1 here. Awesome rile. My only other experience is with Colts – Colts are great guns but I would rather be shooting my MK114 any day. The MK114 is very light, very reliable, and accurate enough… exactly what it was meant to do. Eats steel cased cheapo stuff all day long. Couldn’t be happier with my choice for an AR.
Great rifles,and its funny to read comments from people that don’t own them.VW owners ripping corvettes,if you drive a bug how can you review a PWS?Ive had several manufactures ar15s with DI and since 2009 ive dumped them all for the PWS piston guns.Ive got 2 of 50 2009 special ar 556 rifles and 1 of the 25 762 special editions and they run softer and cleaner than any other ar Ive owned.Only issue ive encountered is the 308/7.62 is loud beyond belief but end result is its stable for the next round.Ordered a YHM ti can for it last week,so long wait, but PWS makes a great lead slinger.
$2000 for a 1:8 twist gun that shoots 55grain ammo into an inch. I just tested a PSA 1:7 twist stainless steel bbl AR that retails for $550 and shoots 69grain and 77grain into a half inch. Granted the 55gr ammo is much cheaper but I can buy a lot of 69 and 77 grain ammo for the $1500 l saved.
And why does anyone buy a Porsche, when you can get similar performance from a Mustang for much less money?
And why does anyone buy Coca-Cola, when the store brand often tastes about the same (or sometimes even better) and is half the price?
See where I’m going here? Not everyone values the same thing in a rifle (or car, or soda). Which is precisely why there are so many manufacturers of each of these items. If it was all about price-to-performance only, we’d only need one rifle manufacturer in America.
And BTW, when guys complain about price how come they ALWAYS cite the MSRP that pretty much no one actually pays?
Hey, is there a problem with the piston of the PWS? They have redesigned it. Now only the piston head keys off. Where before the piston head and about three inches of op rod keyed off as one piece. If you go to their web site, view the new piston system you will see what I mean. The old design looks like where the op rod keys off could be a weak point compared to the new design where only the piston head keys off, the entire op rod is now one piece. Looks more stable to me. comments please.
Don’t knock it until you have shot one I have one and they are the best AR out there. The rifle never james or miss fires I shot 3 gun with on and sit back and watch most AR’s jame at least once going threw the course. I have even seen LWRC’s give some problems I have thousands of rounds threw my PWS and I can count one one hand how many times I have had a problem with my rifle. So you can talk all the smack about how much money you think that they are worth. But it comes down to performance to me . You want the best then you are going to pay for the best. I have had a least 15 AR’s in my time and hands down there number one in my book. I only wish I could meet up with all you people who talk shit because you can put your money were your mouth is. I am going to leave this with saying way to go PWS.
watch the torture test on the 516 then go buy one and put an acog on it and then stick a fork in it.
If you love to wear hoodies? so get this amazing Feel The Beat Hoodie Moreover, it has a hoodie-style collar with a pullover front closure and rib knitted cuffs to hold your wrist. All these amazing features make it one perfect casual outerwear to get compliments from your fashion friends. Discover now the best deals and amazing prices.