It's very common, and went out of production last year. I was lucky to get one about a year ago. The 40S&W version is technically a "P944", or a "KP944" if the top is stainless.
My only complaint was that I had to send it back to ruger for a small amount of dremel work on the chamber entrance, bevel wasn't perfect, caused a jam now and then as the leading edge of the brass would hangup on it and not enter the chamber.
After the repair, what can I say, it's flawless, I've put through thousands of rounds at this point, almost all reloads, without a single jam or malfunction of any kind.
get it!
-edfardos