Broken Screw
 

I have a Dreyse with a screw that the head was twisted off. It looks to me like someone tried to use a sheetmetal screw in one of the holes that holds the sideframe on. After failing with an easyout, I was forced to drill the booger out. I believe I have it all out, but now the frame is resisting attempts to retap the hole. Any ideas? Do I need a special tap for this?