Breaks and scrap em rebuild

[Kenneth R Cluley 480]

Working on 12.5 HP Breaks and Scrap Em Intek. Sister-in -law ran without oil, needless to say replacing rod rings etc. My issue is the "top' ring doesn't fit well in groove. No signs of damage to piston but ring is "tight" in groove. Measures about .045", ring is original B&S part. Groove is not dirty or carboned up, and no visible damage, but ring is definitely tight on about half diameter of piston. I have an automotive groove cleaner tool, but it is too large for groove. !/16" is smallest bit. I tried using old ring end to slide around but didn't seem to be enough. May try a small flat ignition file to open up groove so ring moves freely. Is there such a thing as a small engine ring groove cleaner tool with smaller cutter width's? Anyone ever faced this and how would you attempt to rectify? Possibly out of spec ring? I really doubt ring is problem but can't see anything obvious with this piston. This is off an older Snapper mower but hopefully someone can lead me to the best solution for this. 

[RED-Z06 2,118]

Its possible the ring land is damaged if the rod broke and the piston smacked the head.  Years of carbon on the head could also have closed the gap some.  Proper ring clearance is critical because compression getting behind the ring and forcing it out is a main component of ring sealing.

[Kenneth R Cluley 480]

I'm aware of that, my reason for concern. Just not sure best way to correct or if I should even try. Thought about the possibility of piston hitting head but don't see any evidence of that. Thanks for reply RED! 

[mpoore 26]

Could you grind a little off one of the groove cleaner bits to fit? I think if you took your time that you could get it close to the size you need. Use the side of the piston where the ring fits as a guide.