I bought mine about a month ago, cleaned, lubed it and to the range. At this time I shot six different brands of ammo through the MK IV 22/45 and none have been accurate. At 10-20 yards it is shooting softball sized groups, and that is from a rest. I did call Ruger when I first got the MKIV to ask about the slide stop rattle, the nice lady there said that was normal, really like the 22/45, I have a MKII, MKIII and they are real shooters. I'll be trying a couple more brands of ammo soon and we'll go from there.