…acquired my first Mark IV yesterday. Got a super sweet deal on a gently used Target model in stainless steel. Haven't had a chance to put it through its paces yet, but will this week.
Thanks for the heads up. Mine is 500075XXX, and like you said, Ruger says that serial is past the recall. I did some reading on that retaining pin, and it does seem to be a common problem. I pushed it back in and will watch it closely. The ease that it pushed back in I have a feeling I will be either adjusting the spring arms or replacing the spring. Time will tell.Congrats on a very nice find!
It looks like your takedown button retaining pin is walking out. You might want to seat it before your pistol falls apart at an inopportune moment.
Those pins, and the front lug screw were both known to come loose on the early builds. So you might want to verify yours is not in need of going back to Ruger for the safety recall. Serial #500xxx are made post recall, and the safety has an "S" printed on it if it's older and has already been updated.