Ruger has experienced some alignment issues on some of their early TD models. It seems to be a QC issue in the rush to get to market. Its more of an annoyance than a safety issue but is easily correctable with no need to send the rifle back to Ruger. If you don't have this problem then no worry but if you do here is the fix, Pretty simple.
http://www.calguns.net/calgunforum/showthread.php?t=571152 RUGER 10/22 Takedown Alignment Issue FIX.