Got a 2fer here. Currently own 2 piston AR's: 1 franken 12.5" DD barreled osprey piston system (the newer 1 bolt piece design), and a syrac ord. mid length kit on my BCM 14.5 middy.

The osprey I had professionally installed, and coated in that NiB coating. It runs off a FSB carbine length setup and runs flawlessly, with my JP silent buffer, heavy buffers, wolf ammo, green tip - anything. It runs and guns amazingly. Here's an old photo:



only issue with this settup is I'd like to add a BCM keymod, or anykeymod. I've gotten real used to the feel of the BCM and putting my accessories on them real quick like. So, I've found some old ass threads about rail compatibility but nothing concrete. Wanted to ask anyone else that may have found some rails, or someone smarter than me who can pull numbers and do math and figure out what dimension etc you'd need. OR how to modify something like a BCM KMR to make it work. I'm needy, I know..

Secondly, the syrac. I've had many talks with Jason and (Sarah?) over there at syrac. Real great guys and gall over at there place. They worked with me a bunch on getting the system to work with my DD barrel. Turned out it just wouldn't. They have a weird way of setting their shoulders and gas ports or something. I'm no wizard, so couldn't tell you everything about why it didn't work. Finally sold that barrel, got a bcm and when I got it on, wouldn't work with my JP silent and wolff ammo. Had to move the block around, and open the gas all the way. Finally cycles, but just barely. Is this other peoples experience with the blocK?

Final question. Does gas BB change wit heither of these setups? Finally put in for my for 4s for a bug boy can. Just curious before I get them.

First thing to addres is the Osprey. I've never used one but I do know the reason the rail availability is so limited is strictly because the large diameter of the piston's width won't allow a lot of handguard. Unless you want to cut the keymod and top sides of the KMR, I wouldn't recommend it. I would put the KMR on your Syrac kit.

Next thing to consider is that Syrac gets their parts from Superlative Arms who manufacture for them. They have pretty much the same stuff however I love their customer service and since they do the mfg, I'd recommend doing future transactions with them.

Thirdly you said your JP Silent Buffer doesn't work with the Syrac so I recommend getting the spring kit on the JP website and go with the first lower powered spring that is below the one you currently have.

Fourth, Superlative Arms is designing a .625 shoulder gas block piston system as well as a lightweight (low mass) carrier which should fix any other issues (along with my Third point, see above) you may encounter with the Syrac/Superlative system cycling AND the BCM KMR/Alpha both work over these kits.

And lastly you can always call ADCO and have them open up the gas port diameter for any barrel. Think they do it for like <$50 shipped.

I live in California so I can't give you any advice on your can.

The newer Seekins rails you can get at Primary Arms have counter bore cuts on the barrel nut to accommodate the op-rod in the Osprey kit.  My SBR has a 10" KeyMod rail that allows the piston rod enough travel to cycle the action with no hang-ups.

http://www.primaryarms.com/sp0010530027/p/sp0010530027/