User blog comment:FairyTailFan7/Sting's Attacks Are Light Speed?/@comment-61.2.50.221-20150826213940/@comment-75.136.10.220-20150826215406

The thing is, Sting fired it directly at Natsu, it doesn't matter if it's narrow. If it's light speed, it's incredibly fast. Natsu's reaction speed was FTL.