[JudgeColt]

"Take a little off the top" of the slide stop. Either the notch is a little off or the slide stop is a little off, or both. As mentioned, alter the slide stop and not the slide.

 

[JudgeColt]

I would shoot, repeat, repeat and repeat before I started filing. It will loosen with time.

How will shooting reduce the height of the slide stop when the inside top area is not touched when the gun is shot? Taking a tiny bit off the inside top of the slide stop will solve the problem, and will not affect operation of the slide stop.