A friend of mine had one of these and wound up having to put heavy duty cutting compound in the receiver and working the bolt many times over and over to get it to smooth out. I think he paid around $400 for it. Seems everyone I know that had one has sold it. That fact, what I've heard about some of the lousy ones floating around out there, and because I don't know enough about the different variants is what kept me from ever buying one.
Makes ya think these things would be cheap by now.