I was checking the movement of my slide for smoothness and possible hang ups.
I pulled out the mag, the recoil springs and guide rod. Then cycled the slide
slowly by hand. I noticed that there was a slight hang up when the slide was
still back about an inch, catching in the forward motion.
I found that after firing a few hundred rounds through my p-11 that the hammer hitting the slide had changed the shape of the metal of the slide right below the firing pin. So that now there was a slight burr hanging down that the hammer had to travel over as the slide moved forward.
This was never a problem firing as the momentum of the slide and strength of the recoil springs was enough to overcome the barb, but I wanted to get rid of it. So I ground down a small portion at a 45 degree angle, then polished it smooth, so that now the barb can not come back
hopefully the pics and my drawings will clear it up: