A friend had one years ago. It was O.K. but it had a weird loading gate. Never could get used to idea of a double action "version" of a single action ...just seemed too strange. He didn't keep it long.
Big Mistake. I was thinking of a single action "type" model that H&R produced in the '70s. NOT the High Standard. Sorry about that.
I remember the Double Nine but have experience only with the Sentinel Mark III. I owned one for a short time.