Any ideas as to what causes this to happen?
Another common failure of the safety is a broken front tang. There are two tangs on the lower front portion of the safety and both get hit with the upper hook every time the gun is fired. You can see the wear mark on the tang that didn't break. One tang is narrower than the other and that one is the one that fails. It doesn't really seem to have any affect on operation and probably goes unnoticed by the user unless they take the safety out for some other reason and find that it has broken.
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