The scratch is allowing the carbon to settle in the groove
![shruggy shruggy](/ubbthreads/images/graemlins/custom/shruggy.gif)
I use file to fit ring sets in all the motors I build (1000s+) and I use a small hand sharpening stone to deburr the ends of the rings on all four sides and now and then I still will see some of those lines in the cylinder walls while assembling them
![rant rant](/ubbthreads/images/graemlins/custom/rant.gif)
When I do I make sure there are no sharp corners with burrs in those rings
![scope scope](/ubbthreads/images/graemlins/custom/scope.gif)
Those scratches will stay in the cylinder walls for a while, if it does not use oil and it has a good compression test or and leak down test then run it
![up up](/ubbthreads/images/graemlins/custom/thumbs_up.gif)