I spent a long time in the Magpull booth.
Wes, the one they didn't want you cycling was one of the ones where some of the plastic on it was prototyping stuff, and not the hard stuff. The others you could beat on pretty well.
Okay, here are my initial impressions. I like it so far. It feels good. Looks good. And has some neat features.
The trigger parts are basically AR parts, except for the auto sear. It will be proprietary.
The barrel is a standard AR barrel. Any AR barrel will work. The piston system attaches where the gas block would normally attach. So far they have pistons in mid length and rifle length versions (as far as where they would attach at the ports). They will be working on a carbine, and super shorty version.
The quick detach barrel is the best idea I've seen. You pull the handguard off (one captive pin) then you pull down a small handle which allows you to ratchet an interuppted thread locking collar to one side. This releases the barrel. Slap new one one, torque it back, fold back the handle, slap the handguard back on.
The charging handle is reversible, left or right side. It can be set for reciprocating, or non. It will work as a forward assist.
The firing pin is proprietary. The bolt carrier is like the AR18. I did not pull a bolt out of a carrier to look at it, so I'm not sure how exactly it cams, if it is a seperate piece, or if it is a machined part like on the XCR.
The front handguard can take modular rails, or they have a fully railed version. The regular version is pretty light.
I really like the stock. Adjustable for height, length, and foldable.
There will probably be a dustcover on the final gun. They haven't decided yet. However there will still be a good sized opening on the sides for the charging handle.
From pictures posted elsewhere, it appears the aluminum upper receiver has the serial number (like a FAL).
Asked about that. ATF has not made a ruling yet.
Basically when you hold this rifle in your hands, it just feels really good. I'm excited to get one and beat the hell out of it to see what happens.
-Larry