Normally regulation is the criteria with double rifles - the separation on the target of the groupings from each barrel. It's based on the grouping centre from each barrel, at least that's what I believe. I think 2" regulation at 50yards is generally considered good. I'm not sure about accuracy, but a barrel that shoots 2MOA will group 1" at 50 yards, giving an overall area of impact of 3" at 50yrds for both barrels.

I think that accuracy may even be better than this in alot of cases. For example, I suspect that my Merkel 500NE double may produce groups (not talking regulation here) better than 2MOA just based on calling the shots when I let loose. I've fired this out to a maximum of 50yards, and in a standing rested position.

I would like to bench shoot this one day to see how good it is (just out of curiosity. The regulation and apparant accuracy makes it entirely suitable for its purpose though, so I wouldn't practically achieve anything just satisfy curiosity), but am nervous about damaging the stock. I would have to use a lead sled but the pistol grip looks so skinny that I would be concerned about breaking it.