I blued and entire barrel with the $10 blue casey gun blue or whatever. It works fine, just read the instructions and follow them. If you do what most people do and just put it on a paper towel and rub it on then yes, it looks like a 5 year old did it. If you take your time and do it correctly like the instructions say, you can actually get very good results. The barrel I did was a 36 inch black powder barrel from a kit and it really did turn out nice. It wasn't a professional blue job, but considering it only took about an hour and a half it was very good. Just buy the $10 gun blue and have fun with it. If you don't like it, it was only $10 and you leaned something.
There is no such thing as a stupid question, only stupid people.