Review of PWS Diablo upper

[Ghost__1]

Firstly I understand that this site has its own little issue with being able to discuss anything about Piston Systems in the AR platform so I will ATTEMPT to stay away from that debate. This is in no way shape or form the place for that kind of discussion and I ask the Mods to shut it down immediately should it end up there. I have experience with stoner design and mostly DI systems to include examples of M4, M110, SR25. Please dont insult my intelegence as this is just my honest opinion and observation to the best truth of my ability.

Concluding that statement I can now begin my review of a quite unique rifle.

PWS Diablo

Upper
Reciever- Vltor MUR w/forward assist
Rail- Proprietary design of PWS (cannot replace with aftermarket offereings)
Barrel- Lothar Walther, 5.56mm chamber, Stainless Steel, Isonite QPQ Treated, Button Rifled, 1:8 Twist Barrel
BCG- Proprietary design of PWS (FA design), cannot speculate on MPI/HP testing. They’ve changed the design to enhanced much like that of LMT.
Bolt- Standard DI design, cannot speculate on MPI/HP testing or manufacturer.
Extractor- Standard with black insert
Comp- Proprietary design of PWS resembling that of a blast chamber. Fun fact that the first design they submitted to ATF for eval was considered a suppressor. This is not that comp.

Lower
Reciever- DPMS
LPK- DD
Reciever Extension- Standard Milspec(unsure of manufacturer)
Buttstock- Magpul ACS
Grip- Magpul Miad B2 backstrap and no finger bump
Spring- Standard Carbine
Buffer- Standard Carbine

Accessories
Sights- Eotech 511, Magpul BUIS V2
Light- Surefire M200
Reciever Extension Plate- Standard Slingm mount Plate (unknown manufacturer)
Sling- Listed as a TUFF products 1 or 2 point sling. (Honestly cant remember what it was packaged and would recommend it)


I will start this by saying I aware that in no way is 2000 rds a formidable basis to really base an opinion on pertaining to reliability, however the only maintenance it has received was to take proper photographs. It has only been lubed fired and put away. It travels with me wedged between the seat and center console of the vehicle and has been fired in temps from -20 to 80 degrees. I have not experienced a malfunction of any sort.

The reason I purchased this rifle was because I wanted a wild entry into the NFA world. While looking back on it I can honestly admit that I would have done it differently it isn’t due to unhappiness with the rifle but more of a matter of adaptability. With the Buttstock collapsed it is 24 3/4 long. I can’t deny the multitude of applications this rifle can be used for.

Use
The rifle hasn’t been banged around or abused heavily. Never fired a class. No 7 mag dumps. No Full Auto. No bench shooting or Group shooting other than zero at 50. Mostly stationary drills on steel targets out to 100m with rush drills 200/300 rds/range session. Mostly steel cased ammo fired through it with the exeption of 200 rds of 855.

Overall Design
Its design is based on a piston operating designed by PWS and incorporates what they refer to as a “long stroke piston system”in which it takes design elements from the AK. Im not 100% in love with the fact that the Charging Handle is semi stuch to the BCG. So far from my experience with this and other piston operating systems is that this systems feels smoother. Like many other piston operated systems it has carrier tilt issues that I am told are resolved with the new enhanced carrier design. Considering the length of the barrel the upper is on the heavy side due to the piston system, profile and material of the barrel. Its not to the point of being taxing just considerately more than a DI system.
As far as craftsmanship goes it could be better; the most notable area being the point where the Op Rod is welded to the gas key. It has a slight burr and noticeable welds that have been anodized over instead of smoothing or finish machining. I believe this to be only cosmetic and not effect function or effectiveness however.


Fit and Finish
Fit and finish of the rifle seem to be quite well. They seemed to have incorporate the piston system well in regards to the MUR upper. Upper and Rail system fit well and also quite solid as the rail System in non free floating. Finish of the rail and proprietary parts from PWS seem to hold up quite well for normal wear and tear with no discernable marks from being banged around the car and mounted/unmounted equipment. The only other issue with the fir would be the Charging handle design. Its not really a flaw however it semi complicates breakdown in the fact that you have to pull the BCG out and drop the charging handle when its all attached. Kind of an annoyance. The Key Staking is not conventional however I feel is quite effective. Maybe someone can speculate further to me if this isn't as good as normal.

Function
The rifle has functioned flawlessly until this point(I use that term loosely).It hasn’t suffered any malfunctions as of yet and not that I think it will soon I just understand that at some point something will break. One area of concern for me is that carrier tilt issue. Its not about the RE being damaged because of cost as much as it could turn real bad if it were to fail. Like stated previously PWS now is selling their enhanced BCG designed much like that of LMT’s. This should mitigate this issue if not fix it all together. The rifle does not feel overgassed even considering the Standard buffer and spring. Locks back on empty.

Ballistics
The advertised velocity of this rifle is 2200 fps as per the PWS website. I cannot speculate to the truth of that claim as I have not had it on chrono. I can only comment on perceived terminal ballistics on normal grade ¼” steel in that the round still punches through quite effectively out to 100m.

Conclusion
Based on my experience with the system I wouldn’t hesitate to give this company a good standing as far as products alone go. I have no experience with CS side of the house but the QC seems to be on the up and up with the exception of the op rod weld. Its my understanding that this has no effect on function however is a step that in my opinion should have mattered more. As far as practicality goes I cannot deny the purpose and role this rifle could play in a HD/SHTF role as it can literally be concealed almost anywhere. If there are any questions for me or if more info is requested feel free to comment below or PM me. Considering all of the pictures were taken on my cell phone as I cannot find my camera charger please dont hesitate to comment just dont beat a dead horse.
http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-1374-1329729852236.jpg

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-3149-1329729853929.jpg

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-2806-1329729860680.jpg

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-2861-1329906660272.jpg

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-2860-1329906659418.jpg

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-3384-1329729850561.jpg
Proprietary Comp/Flash hider

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-1552-1329729848668.jpg
Inside of Flash hider

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-3416-1329729862432.jpg
Erosion of the end peice

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-3386-1329729859846.jpg
Inside chamber/M4 feedramps

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-1615-1329729857291.jpg
Operating system internals-Notice the BCG and CH issue

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-2318-1329729858120.jpg
http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-2618-1329729854761.jpg
Notice Key Staking

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-1356-1329729847837.jpg
Piston seperated from Op rod to remove CH

http://i1226.photobucket.com/albums/ee418/Matthew_Fairbanks/photobucket-2378-1329729853071.jpg
Reciever extension with visable Carrier Tilt wear.

[Iraqgunz]

Thank for posting this. You probably should have written the article for Special Weapons for Military and Police rather than the trottel who recently did it.

They had a few gratuitous shots and nothing in detail about the BCG or anything else.

I would be interested to know how this would function with an A5 set up or with heavier buffers.

[Ghost__1]

I would say that it would function well enough with the exception of maybe locking back on empty. I unfortunately don't have any heavier buffers around so I can't really be for certain. I will however say that it is surprisingly manageable in mag dumps.

Another downside to my experience was that I had to partially learn a new technique to shooting this upper because of the shortness. Its not out of question but is goofy to get used to if you are used to longer rails.

[motoduck]

Nice post. Well thought out and well laid out.

[DacoRoman]

very nice write up, thanks for posting!

I thought that these had a minuscule amount of carrier tilt, but it would seem that it is still an issue, albeit maybe not as bad (?), with their long stroke AK style piston system? Can you please keep us updated on the tilt issue, say every 2K rounds or so?

Also, it looks like their latest version setup; if I seem to remember right their first iterations had a normal GI BCG, do these new ones have a more tapered BCG rear end?

[Ghost__1]

very nice write up, thanks for posting!

I thought that these had a minuscule amount of carrier tilt, but it would seem that it is still an issue, albeit maybe not as bad (?), with their long stroke AK style piston system? Can you please keep us updated on the tilt issue, say every 2K rounds or so?

Also, it looks like their latest version setup; if I seem to remember right their first iterations had a normal GI BCG, do these new ones have a more tapered BCG rear end?

This is the older version of their gi carrier. The new ones come with a carrier similar to lmt's enhanced with the tapered bump at the back to fit tighter in the re. The easiest way to tell is if it has a vltor mur upper receiver. The new ones come with a standard receiver. I assume because of the demand was too great to order from vltor. I will surely keep everyone posted on the profess of this every two thousand. I'll also try to get it on a scale as it seems a little on the fast side.

[turboabbott]

I have one of the newer MK107s. Right now I can only find a cell phone pic of the exterior. I do not currently have an up close image of the carrier, but I will snag it out of the arms room tomorrow and snap a quick one for comparison. Stand By.

[turboabbott]

Here are a few pics of the carrier.

[FreakSF]

Hey I know this thread is old but it seems no one ever commented on PWS CS. So I'm going to. I've been to their old show room and their new closed to the public one and I've got to say I like the feel of the old one. With that said it was and is the same people and that means the same great reliable service and work. PWSs great gear and a great company.

Ok, I'm done. I just have had nothing but good things with PWS and I can't say that about every company I have dealt with.