If you can't bring it by the shop give me a call at the shop one of the days I mentioned 856-8880. After rereading your post the firing pin could be peened or the spring is failing but I would really like to get a look at first before I give definate answers as to what I think it might be. I have a few Ruger Mk handguns and have been known to assemble a few here and there.

I'm told that you are the go to guy for Ruger pistols. I have a Mk II that I bought several years ago from a dealer who got it from a Sheriff, who took it off the body of the previous owner. It had been through a fire & isn't pretty. Well, I got a Tactical Solutions upper for it and after some shooting it has become rather unreliable (sometimes up to 1/2 a magazine will not function, usually failure to fire, but others as well). I have called Ruger several times & left messages for the woman in charge (I'm told) of returns/repairs. I have never gotten a call back or spoken directly with her. I figure that some of the springs or other parts might have degraded over time (no thanks to the fire, either!). Any idea what parts I should replace on it?
I was refered to you by Nick (VUPDblue) & any advice/ assistance is appreciated!
Thanks,
Dan