The title should make it clear what I'm after. I want a piston upper that has an easily selectable setting to lower the gas, that means no tools and clear notches for the gas selections. The upper MUST have a forward assist and preferably it would have an MLOK rail. It seems that most of the piston uppers that would fit this criteria are too expensive with the exception of older PWS uppers and older Adams Arms uppers. The PWS is long stroke which seems like it would be more robust but people also have great luck with Adams Arms kits and have for some time. PWS uses a bullet to select gas setting through the rail while Adams Arms forces the user to touch the hot selector with their hand as far as I can tell. Adams has more gas settings to choose from. Also, the newer Adams P2 uppers seem to have the gas block considerably under the rail so that it can't be readily adjusted. The unfortunate thing about PWS is that they have dropped the forward assist on their newer models and all of the older models that are available in 11.5 have KeyMod hand guards. If the older PWS models had MLOK it would likely be my choice. I just greatly prefer MLOK. If I could find some rail sections that utilized every keymod slot it covered to increase strength I might be able to convince myself that it's okay.

I would consider building my own but I don't see how I could run a decent length hand guard without making the adjustable gas block hard to reach on an 11.5 inch gun. If I can't easily reach the gas block then the upper no longer meets my criteria. I emailed Adams Arms about this, since their MLOK uppers seem to suffer from this problem unless I'm missing something, I'm waiting to hear back. I had it in my mind to use the Faxon 11.5 mid-length barrel to get the gas block close to the muzzle but they only make it in .625 while Adams Arms only make their piston kits in .750. The superlative arms kit is not an option because there is no easy toolless on-the-fly gas selection and I don't care for the location of the piston spring. If that pring weakens enough the carrier could start hammering on the piston. This is more likely as the piston head gets dirty and has a harder time returning forward.

Am I stuck buying a PWS KeyMod gun? Any information about how one adjusts the gas on the Adams Arms P2 MLOK uppers? Is long stroke preferable to short stroke? Any recommendations for uppers to look at or build options? I would say that right now I'm leaning towards just buying the older PWS MK111 Mod P-1 and putting up with the KeyMod even though it will bother me. I am open to buying used if you happen to know of a deal somewhere.

Check out BLACK RIFLE ARMS

Theirs is an 11" upper, but meets your other requirements. The regulator requires no tools, etc....literally reach up pullout twist to next sitting and can rotate 360 degrees and has a silencer setting.

not sure about their mlok variations, but adams arms EVO uppers come with the piston easily accessible. I love mine.

I went ahead and picked up an MK111 MOD 1-P upper. It was about $800 and that seemed like a good deal if I could overlook the keymod. I will just find the strongest rail sections I can and rail mount everything. I don't want to use keymod accessories because I don't plan on ever buying another keymod rifle. The MOD 2s are a little lighter but I'm not that concerned. I wish the rail was a little longer but that's not a big deal either. The Black Rifle Arms uppers just don't seem to have much feedback out there and they use 1:9 twist barrels. The Adams Arms uppers look great but, again, I'm not sure how one reaches the gas block on the MLOK models. Those AA P2 MLOK uppers are almost $300 more than the PWS while their lowest model is only $100 cheaper.

I just wanted to update this in case anyone comes across this thread and is looking for info. I did get an email response from Adams Arms, their longer handguards require you to use a flat head screwdriver to adjust settings from the front of the rail. I would like to see pistol upper manufacturers try the 11.5" mid gas setup. It's reliable for DI guns and piston guns need even less gas. This would get the gas block forward enough to run longer rails and still allow for easy gas adjustment.

Edit: I went with a PWS MK111 Mod 1-P upper in the end.

I'm using their BRA older piston system upper and love it, 1/9 twist stabilizes 55-62gr ammo well to use a can on it , looks like it's time to give a new lo-pro upper a try.