They make two rifles. The MR-17 in 17HMR and the MR-22 in 22WMR. I had the MR-17. At the time, there were only a couple of semi auto 17hmr's on the market. I though this one looked cool so I bought it. When you hold this rifle it is obvious that these people know cnc machining. Very solid and well built little gun. It was a fun little gun to shoot. I had quite a few FTE with mine. A couple per magazine. When it shot well, it was a lot fun. When it didn't, it was a pain in the ass. After a couple of weeks I saw something else shiny that i had to have and traded the mr-17 in on it.
I am sure the FTE problem could have been solved. I am distracted very easily and just moved on to something else. When it ran good, it was a fun little plinker.
http://www.excelarms.com/acceleratorrifle.html