What 'screw in front of the magazine'. Do you mean the screw, front trigger guard? If you stripped it, what did you strip, the thread? What do you mean by 'repaired it with a patch?' What sort of patch

I think it needs a bit of elaboration before any sense of an answer can be given

If you fix something with a patch in Armourers language, I seems to mean a wood patch or patchedf up with welding...............