I had two- a .308 and a .223, both threaded barrel 20"; the .308 was about a 3/4moa gun; good, but not anything to get crazy excited about. The .223 on the other hand, is easily 1/2moa (prob better, but 1/2 is very safe) with hornady 75gr match. I sold the .308 to help finance my M24. I'm not at all upset about it either.
I don't think you'd be disappointed. But at the same time, with factory chassis and unitized guns available now, for not a whole lot more, I'd likely go that route- the RPR is obviously solid; haven't hear much about the mossberg factory chassis offering.