I was rereading Vol. 3 of the manga after reading something in a fanfiction and low and behold there IS at least ONE gun in the series. I found it on page 33 there is what looks to be a Match or Flintlock type rifle behind the counter when Tazuna and Sakura are in the shop. Am I on the last to notice list, is this just too insignificant to be mentioned as being part of the Naruto world or has Kishimoto just flat out said "No guns in the Naruto world" and forgot he drew that one rifle?