Thanks everyone, I am NOT going to be using Stingers in my Mark II
Thank you again.
22 LR around here is hard to find but I did find some Stingers so I bought them just because they were available.
I will use them in something else.
Wow! Talk about exhuming a 6 year old post!

lorenzo, you've made a very well thought out choice. The above posts are mostly all correct, in that CCI does indeed make a myriad of .22 rimfire ammunition choices. So, there are plenty others rather than "hyper velocity" to choose from. The manual sent with every Ruger Mark pistol, except for the early Mark I & Standard pistols admonishes to NOT use ANY hyper velocity .22 rounds in the Ruger Mark pistols. And why would that be?
The hyper velocity, 1435 FPS +, rounds produce much too much
"recoil impulse energy" for the Ruger Mark pistols. And, the Stingers do indeed fit into the Ruger Mark pistol chambers.
Here is a picture of a Ruger Mark II bolt stop pin that I removed from a customers 5½ bull barrel Mark II, where he admitted to using Stingers exclusively:
The bolt stop pin is bent slightly and the front face has the back face of the bolt that contacts this pin fully embossed into that face.
What's not visible is the elongated hole for this pin in the top side of the receiver. A bolt stop pin can be purchased for a little over $9.00, a receiver will cost a bit more than that.
So, is it best to take Rugers advice and refrain from using "hyper velocity" rounds in your Ruger Mark pistol, or should you go forth and roll the dice and stick with Stingers? Neither those who advise for the Stinger use, nor Ruger, will provide you with any satisfaction or, for sure, any warranty.