Word has just gotten to me that Crosman was showing a new AR-type PCP air rifle at the SHOT show. They've dubbed it MAR177; the MAR bit standing for Modular Adaptive Rifle, and the 177 obviously refers to the caliber. It's actually not a complete rifle, but an upper to fit to your AR-15 lower. For the sake of simplicity, I will refer to the MAR177 + your lower as an air rifle.
The Crosman MAR177 is a Pre-Charged Pneumatic (PCP) air rifle, like my Marauder, and appears to use a similar magazine (but 8-shot, rather than 10-shot like the Marauder). You'd fill the air cylinder with a high-pressure hand pump or SCUBA tank. You can see the pellet magazine above what would be the ejection port.
I can see these being bought by CMP/DCM shooters looking to practice indoors, or maybe just looking to shoot cheaper ammo. The upper can be placed on your match lower, so that you get the same trigger pull. Not sure yet if you can put like a modified A2/A4 handguard on it yet. They are saying that it will put 10 rounds into a 9mm circle at 10 meters. The barrel is made by Lothar Walther, the same barrel they use for their Challenger PCP rifles, actually. The MAR177 meets the requirements for use in National Match Air Rifle competitions.
The velocity figure stated in the press release is 600 feet per second. I would imagine that is with match pellets that weight less than 8gr. Whether you can tune the rifle to shoot faster, is currently unknown, but the Crosman Challenger match rifle requires gunsmithing to get to magnum air rifle velocities. The air cylinder can be filled to pressures up to 3000psi, and should get 120 shots per fill at 600fps.
I'm almost certain that the upper is some kind of single-shot bolt action. I'll try to find out a little more from people who actually fondled it at the SHOT show.
Retail price is expected to be in the $800-900 range, and they are shooting (no pun intended) for a release date sometime this summer.
Crosman MAR177 Press Release