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At some point, everyone looks back on their achievements and says, “Why not do more?” Primary Weapons Systems is known for their piston driven wonderguns and TTAG has had the pleasure of testing their MK 114 rifle and MK 107 Pistol in the last few months. Short story, we’re impressed with what they’re putting out. But back in early May, PWS announced that they’d also be releasing a direct impingement (DI) upper for the masses. It still uses the same high quality parts and manufacturing processes Nick and I raved about in our reviews, but in a simple, more cost effective package. When you make one of the best piston guns out there, making a good DI gun shouldn’t be too hard, right? . . .

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If you’ve seen one AR upper, you probably figure you’ve seen them all. Well, in a way, yes. To my amateur eye, the PWS DI upper doesn’t really deviate from the norm when it comes to structure, features, or appearance. The first and most important thing I checked was to see if it would fit on a variety of lowers. First test passed. It hooked up to ArmaLite, Palmetto, and New Frontier lowers with ease and exhibited no rattles or shimmies once in place.

As you can see, the upper features a Picatinny flat top along with forward assist and a dust cover. Again, features virtually all of Stoner’s descendants possess now.

 

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Where the PWS starts to differ from the pack is in the barrel, bolt carrier group, and forend. You can easily find stripped uppers on the cheap, but they won’t have a free-floated forend, and they most likely won’t have a high quality barrel.

PWS uses a QPQ isonited barrel turned in house from a chrome moly blank. This means, a) that they have a high degree of control over the final product, and b) their barrels are corrosion resistant. As part of their turning process, they create a profile that sacrifices nothing in accuracy while being lightweight(ish).

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PWS offers three configurations in their Modern Musket line, their nomenclature for DI guns. This test gun was of the 14.5″ barrel variety sporting a pinned and welded flash hider to meet NFA regulations. They offer two types in that class, one sporting the FSC556 muzzle device, and the other sporting the Triad. My test rifle used the Triad. There’s also a 16″ version that only comes with the FSC556 muzzle device.

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All of the DI guns feature the PWS keymod rail, a free floated affair with a Picattiny upper portion and keymod everywhere else. One nice feature is the QD mounts at the front and back of the rail. The 14.5″ gun sports the 12.1″ handguard while the 16″ sports the 15″ length. Both the barrels and handguards are available as independent accessories from PWS in case you have a barrel/upper combo that’s working great for you, but you want a new or different handguard.

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The PWS website indicates that their uppers are sold as stripped units, however PWS was nice enough to ship our test gun with a charging handle, and complete bolt carrier group. Truly a plug and play affair. If you’re interested in adding a BCG, PWS is happy to sell you one for $199.95. However, you’d still be responsible for finding a firing pin, bolt, and charging handle. If you’re one of those buyers who prefers a matched bolt and barrel, you should be able to call PWS and put together a solution. They’re great folks with an eye towards customer service.

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I was pleased with the overall quality of the parts and assembly of the DI upper. As you can see, it checks all the boxes. Properly staked gas key? check. Full auto bolt carrier group? Check. M4 feedramps? Check. Free floated handguard? Check. 1:8 twist barrel? Check .223 Wylde chamber? Check. It all adds up to an incredibly reliable affair that eats .223 and 5.56 all day with boring repetition. It isn’t a featherweight upper, but the weight and balance is nice making it easy to handle, and the keymod system ensures you can stick whatever you want, anywhere you want. These are all things I’d expect for a product that will cost you nearly a grand when the dust settles.

But now lets discuss accuracy. I mounted an 8X scope, the Bushnell you see above, laid down at 50 yards, supported the front and rear, and put four different types of ammo downrange. The results are below.

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Because that font is incredibly hard to see, I’ve presented the results below in handy bullet point fashion using both the Average to Center and Max spread measurements for group size.

  • AE 223 (2915 fps)
    • Max Spread: 2.649 MOA
    • Average to Center: .842 MOA
  • PMC Bronze (2867 fps)
    • Max Spread: 1.688 MOA
    • Average to Center: .562 MOA
  • XM 193 (3251 fps)
    • Max Spread: 2.572 MOA
    • Average to Center: 1.123 MOA
  • XM 855 (3172 fps)
    • Max Spread: 5.058 MOA
    • Average to Center: 1.908 MOA

As you can see, this gun HATES XM 855, a disappointing fact since I happen to have a pretty decent amount of it on hand. I was generally pissed about that flyer in the American Eagle group, and if I used a “best of” three-shot group, it would be a close to 1 MOA group. But five-shot groups keep us honest.

For repeatability sake, it eats PMC Bronze best, and that’s what I’ve had the most luck using. I’m sure that with the right ammo, this is a nearly sub MOA gun, but I wasn’t able to produce those kinds of results in my testing. Nick was able to get sub MOA results with their MK 114 so it might just be me, but I wasn’t overjoyed with the accuracy of this gun. Good for sure, and better than a lot of uppers out there, but not one of those guns that takes whatever you feed down the pipe, and drills ragged holes with it.

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Specifications: PWS Modern Musket DI Upper

  • Model: DI – 14LE
  • Chamber: .223 Wylde
  • Barrel Length: 14.5″
  • Muzzle Device: Triad (pinned/welded)
  • Barrel Twist: 1:8
  • Gas System: Direct Impingement
  • MSRP: $699.95 – stripped $674.95 online & $899.95 online for a complete upper

Ratings (out of five stars):

Build Quality * * * * *
This is a top notch upper in terms of construction. All the right pieces are there, and all the right actions have been taken including a properly staked gas key, M4 feed ramps, and full auto bolt carrier. Everything is assembled to perfection. I was unable to find any defects cosmetic or otherwise. Even the pin/weld job on the flash hider looked perfect.

Accessories/Modularity * * * * *
Since the PWS rail is a keymod system, your options are limitless. Feel free to stick a Picatinny section in every hole or be more judicious and add a light here or there, or a vertical foregrip. With the Keymod system, you can do anything you need to do.

Reliability * * * * *
I was unable to make it choke. I fed it four different types of ammo and some random grab bag stuff that could have been anything. I didn’t get so much as a hiccup during my testing. I was not at all a diligent owner either. I refused to lube it past what came from the factory, and subjected it to sand, dirt, and some rain. Nothing seemed to affect reliability

Accuracy * * * *

Update here

The PWS Modern Musket appears to eat cheap PMC for breakfast, lunch, and dinner and consistently turning in sub 2 MOA groups. This is perfectly adequate accuracy for the weekend warrior, and carbine match competitor. However, if you need to stretch the legs a bit, you can shell out a bit more for the heavier loads from Fiocchi, Federal, or Norma and see sub 1.5 MOA groups. This isn’t mind blowing accuracy by any means, but it is more than adequate to warrant a solid four star rating.

Overall Rating * * * *

This is a fine firearm. I would say that for most shooters, a gun that can go sub 1.5 MOA with premium ammo is enough of a shooter to not matter. It has all the right parts to put it in a class with other premium products, and the price to suit that placement. A similarly kitted out Noveske will run you north of $1300 so this represents a nice middle ground that will get you high quality features without absolutely destroying your bank account. If it’s any indication of my feelings on the gun, I’ll be using it for my upcoming run-and-gun race through the desert. I can only pick one gun and this one is it for me.

22 Responses to Gun Review: PWS Modern Musket DI Upper

  1. Strongly considering getting one of these now. I want to mate it with a decent polymer lower I’ve been looking at. What kind of stock are you using in that above picture?

      • Is that a real question? It’s my understanding that everybody uses full-auto any more, except for the uppers ordered specifically for the old Colt lowers which will not accept them (I have one). Was that wrong?

  2. Please tell us more about your conclusion that this gun is limited to “the 55 gr class of projectiles.” You lost me there. The whole point of the 1:8 twist is so you are NOT limited to 55gr loads. Just because accuracy suffered with one 62gr load, it does not follow that it will have problems with others (or heavier rounds).

    • I agree completely. I have home-built 1:8 20″ that probably costs far, far less than the PWS. I can wring 0.88 MOA groups with the American Eagle 50gr Varmint round, and I get right around 2-3 MOA from XM-855. So far it’s the least accurate 62gr commercial load I’ve found in my rifle. Does that mean my Green Mountain barrel can’t stabilize heavier rounds? HELL NO. Wolf Military 62gr steel case produces consistent 1.5 MOA groups in the same barrel. It’s the load, not the barrel.

      Probably also illustrates that you don’t necessarily need to drop big bucks on an AR like this to get a great rifle.

    • Fair critique. I’ll shoot more heavy loads through it and see if likes any of those better and update this review with my results. Is there a factory load you recommend over something else?

      • You might want to move out past 100 yards with the heavier ammo. I’ve been told that the heavier ammo will start to surpass the performance of the light ammo as you get into longer ranges. Apparently, at shorter ranges, you should expect better performance from lighter bullets. My 1-8 twist barrel shoots light stuff better at 100 yards. I’ve yet to shoot it past 100, so I can’t say too much about this. For heavy stuff, my best results have come from Hornady TAP FPD 77 grain.

        Also, what’s the weight of this upper? To me, you can’t really evaluate the accuracy of an upper unless you know how much it weighs, how that weight compares to other similarly designed uppers, and how the accuracy compares to those other similar uppers. You can find much cheaper uppers that will shoot rings around (or inside of) this one, but they’ll weigh 6.5 lbs.

  3. 1:8 twist is ideal for heavier 69gr and 77gr loads. I have, however, sold the only two “.223 Wylde” barrels I’ve ever had. 5.56NATO chambers, for me, have proven FAR more accurate, especially with my 77gr SMK match loads.

    • I’ve got a Black Hole Weaponry barrel – 1:8 polygonal rifling, .223 Wylde. It drives tacks with everything I’ve put through it, though I must confess I haven’t shot anything as heavy as 77gr yet.

  4. You mentioned the weight, but did not specify. What was the weight, and what is the barrel diameter/profile?

    • I will put it on the scale when I get back home and add an addendum to this article. It will be at least a week since I’m on vacation, but check back then.

  5. Too expensive. You can get PSA premium CHF complete upper made by FN for half the cost.

    I do however love the Micro dots PWS puts out. (Especially the Gen 7)

    Will continue buying those from them.

    • Chris, PWS stands for Primary Weapons Systems, not Primary Arms. PWS produce high end piston and now DI ar pattern rifles, and high end accessories. Primary arms produces “budget” optics and sells many other things. Both are fine companies, but not anywhere near the same company.

  6. “a gun that can go sub 1.5 MOA with premium ammo”

    I’m going to take some issue with this quote. This is not directed at Tyler. It’s directed at TTAG generally.

    According to the data, this upper averaged 2.99 MOA. Not one group was 1.5 MOA or less. The best group was 1.688 MOA. Groups are not measured by average distance. They’re measured from the centers of the two farthest apart shots. The data does not justify the statement.

    This brings up a larger issue with TTAG’s gun reviews. The idea is Dyspeptic Gunsmith’s, but I’m going to repeat it. TTAG really needs to develop some standards for reviewing accuracy. It couldn’t take more than a couple of hours to do it. Choose set distances (100 yards), number of shots in a group (five), number of groups to shoot (at least three for each ammo type), a stabilization method (front and rear bag), time between shots, a measuring method (calipers to the outside edges of farthest two holes minus bullet diameter), etc. This will allow useful comparison’s to be made between guns regardless of the reviewer.

    In my opinion, TTAG’s lack of accuracy standards testing leads to TTAG consistently over rating the accuracy of the guns they review. What I see from these groups is a $900 upper with suspect accuracy. To use letter grades, it shot one A- group (for this kind of barrel), two Cs, and one F. Yet somehow it’s a four-star accuracy, 1.5 MOA upper.

    • TT,

      I don’t think that presenting average of all ammo shot is a fair metric for an objective gun review. I’ve never met a gun that shot every type of ammo well, even some of the premium upperss out there.

      You also said, “Groups are not measured by average distance. They’re measured from the centers of the two farthest apart shots. The data does not justify the statement.” I don’t really understand the statement since I presented both max spread, and Average to Center using OnTarget. So using PMC Bronze, I was able to achieve a group with a max spread of 1.688 MOA which is pretty wicked close to 1.5 MOA. PMC Bronze is cheap ammo and I’m not the best shooter in the world, so it isn’t a stretch to say that this gun could go 1.5 MOA.

      I’ve already started a to do list for a follow up to this review to address some issues, but one of them will be a reshoot at 100 yards with the ammo here plus Black Hills Reman 55 gr. and a variety of heavier Black Hills reman. It will be a few weeks, but you’ll have an update.

      • What I’m saying is that when it comes to reviewing accuracy (which is by its nature a persnickety thing), I don’t think it’s helpful to speculate about what a gun might be able to do. I see no empirical basis for saying this is a 1.5 MOA upper. You suspect it might be capable of producing that kind of group, but, in my opinion, suspicion shouldn’t factor into the accuracy rating until it’s confirmed.

        This gets to the larger issue about the tendency to overstate accuracy. People pay a lot for their guns and they want them to work well. However, there’s a real tendency among shooters to select only the favorable accuracy data and ignore the rest, even when the bad predominates. For example, if you shoot a subpar rifle enough, it will eventually produce a good three-shot group (blind squirrels find nuts). Does simply shooting a bad rifle until it produces a good group make it an accurate rifle?

        To use a personal example, I recently finished a varminter AR. To evaluate ammo, I shot a five kinds of ammo under the same set up conditions at 100 yards in 18 five-shot groups. The best group was .432″. The worst was 2.151″. The groups averaged 1.33″ Seven of the 18 groups were sub 1 MOA. Is this a sub 1/2 MOA rifle, a 1 MOA rifle or a sub 1.5 MOA rifle? If you were buying this rifle from me, how would you want me to describe it?

        I am not trying to pick on your review. I would just like to see TTAG tighten up its accuracy reviews across the board. I have no problem with calling this a sub-2 MOA upper. But since this site is supposed to be The Truth about guns, I just don’t see the basis for calling this an accurate upper when it shot one good group, two fair groups, and one bad group. It seems like more often than not, the accuracy reviews here have some variation of “This is what it actually shot, but I think it can do better for x,y, z reasons, so I’ll rate it better.”

  7. Because assembling an AR upper is sooo hard.

    Lots of cow patties here.

    “QPQ isonited”. Okay so it’s melonited. Good but.. so what? That’s nothing new.

    Free floating handguard.. again.. so what? About as elusive as flies in a stockyard.

    $200 bare BCG? Haha this is where you lost me. A more expensive BCG doesn’t help you shoot better. I admit I do have a shiney one in a build – chosen for aesthetics to match the stainless barrel. Feng shui all that. I don’t believe it shoots any better than my cheapo oxides. Pure vanity which I embraced in moderation.

    “Properly staked gas key”. So they know how to operate a vice, punch, and hammer. Congratulations? Considering you need those skills to complete a lower I’m not sure what’s to impress.

    All of this so I can shoot 5 MOA with surplus ammo.. hilarious.

    If you’re going to write such marginal advertisements at least highlight them in blue like digg so I know to ignore them.

  8. I like pws because it’s simple , it fires rapidly , well balanced , as I shoot mines , in different scenarios mainly with just irons , in variable physical condition , does not fail , sure I won’t get a penny while in movement but a CD size would do

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