Okay, so there's probably a lot of information on them already, but I guess I'll do a review on how I think about it overall (after some encouragement). First time ever doing review, so forgive me if I leave a few details out. I swear, it isn't to make it look better, cause I'll get to the cons later on. Also, sorry for bad pics. I'll post new ones in that AR picture thread when I get time to go to the range, right now college gets in the way. If you don't see anything new, then I apologize. If you do, glad I could spread some info. So the Mk216 Mod 1 is a piston AR. Like every other piston AR, only it uses a long-stroke piston instead. Note that its all essentially just all one big moving part. No extra springs or anything. The piston is two pieces, but they connect to each other so for all intents and purposes, just one massive part. Now they have two different versions. The Mod 0 and the Mod 1. The Mod 0 is also good, pretty accurate. However, the handguard was not free floating. It also lacked an adjustable gas block. The Mod 1, however, has a free floating key-mod handguard as well as an adjustable gas block. Both trigger guards are one piece, unlike like your regular AR. This is where you adjust the gas block. A new one does come with a tool for use on a front sight, and for the gas block. One thing I like about the PWS over some other piston ARs, aside from it being a long-stroke piston, is that it does have a 15" handguard. The upside is having a bipod further out, downside is a little more weight, but more on weight later. As for its accuracy, or precision if you want to go with that, its pretty accurate for a piston AR. I've gotten it as low as .6 MOA with good ammo, normally .7-.8 MOA. I'm a cheap bastard, however, so that didn't matter too much to me beyond just seeing what it can do. What I really liked was that it is roughly 2 MOA on average with ZQI (YMMV, some say they get 3 MOA). I've gotten worse, but I never got better than that so take it for what its worth. The muzzle rise was the biggest shock to me really. The only way you can tell you're shooting a .308 is that you still feel the kick (not as much though). However, the muzzle rise made a few of my friends pull out the magazine to make sure they weren't shooting my 5.56. Trust me, I'm still to this very day shocked that it has a rather flat muzzle rise for a .308. This can be thankful to the long-stroke piston, adjustable gas block, and the muzzle brake that causes me to go deaf if I forget my hearing protection. Another thing to note, the biggest complaint I ever hear about a piston AR compared to the DI counterpart is balance. And with some of the ones I got to hold its true. However, the PWS balances pretty good, in fact it balances better than one of my DI uppers on my 5.56. This is due to the weight of the piston being on the BCG, instead of over the barrel. I got to hold different piston ARs, and shoot two different ones (one I brought home). The ones I shot were the LWRC and PWS. Both were fantastic, but the PWS was cheaper. I've held a Sig 716, LWRC, PWS, and a POF. The barrel is a QPQ isonited barrel. Unlike chrome-lining, this is just a treatment. So there's more consistency in the rifling. Not only that, but it affects the entire barrel, not just the inside. Whether it'll last as long as a CL bore or not, I probably will never know. However, with its accuracy I won't complain. The dirty part of it.... I do shoot prone. At the range I go too, we don't have grass. We have sand and loose dirt. They do get in there. So far no issues with that. Occasionally there's mud, not too many issues but it does get in the chamber. When it gets in the chamber, issues happen. No changing that. I also ran it dry, no FTF or anything as a result of that. I will, however, say that I don't go to the extremes. Not because the rifle is too expensive, but because I'm pretty sure I won't be burying my rifle in mud during SHTF or anything. Now the downsides.... Its long. With a 16 inch barrel and stock extended, it measured almost 40" (I think it was either 38 or 39?). Its heavy, lighter than some piston ARs, but at nearly 9 pounds its pretty heavy. With my scope and scope mount, its 12 pounds. If I attach a bipod, it gets a whopping 15 pounds or more depending on the bipod. Its is proprietary, though since this is a .308 standard is out the window anyways. Its not cheap, I spent $2,500 on mine after tax, and that was with a dealer who did his best to match the price of an online store (which causes me to give them much praise to anyone I know here in NC). So as we all know, heat and gas are not gone, they're just moved. Well, unfortunately there's a hole in the tube the piston resides in, so carbon does in fact get onto the barrel. However, I did not find it to make any real difference in POI, so just clean it and move on really. It can be a PITA to take apart since the BCG AND CH have to be taken out at the same time. While only needing to clean the piston for the most part is a plus for pistons in general, you still want to clean the part the piston is in every now and then. Not a big downside, just something to keep in mind. You can probably get away with never cleaning it. If your arms are as short as mine, that c grip leaves your hand right on the gas block. It gets HOT there. So gloves are a must. Unless you do a standard grip, then ignore. Another thing, like all piston ARs, there is going to be carrier tilt. I haven't noticed much of it, but I probably will later on as I get closer to that magical 4 digit number. An anti-tilt buffer doesn't get rid of tilt, it just alleviates the problem. Is carrier tilt as bad as it used to be? Not really, so don't fret over it too much. Not a match grade trigger, so you will need to replace it if you want a match grade one. Overall, I do recommend it to those who want a piston AR. However, I won't say its the only good one. I don't make money off of you guys buying one, so I'm not going to say the typical salesman stuff. I'll only say what I think based on MY experiences. P.S. There may be a mod 2 coming out for the Mk2 series, so keep an eye out for that.