All of these four videos are excellent. You will notice that while all the videos and articles have slightly different design dimensions, they are fundamentally very similar. I urge you to view and read everything I am serving up.
Then, my final words of advice are simply....choose between a barbeque switch and a taser gun. (Hint: there is a right choice, and there is a wrong choice.)
Last, make your own choice about the proper ratio of chamber to barrel volume. (Hint: I will not be a design bigot in this instance: you are all gifted students!)
These are the most critical choices you make in this very important endeavor. I also plan within the next month to post the be all, end all, the mother of all potato gun tutorials. Stay tuned.
WonderHowTo has indexed several dozen potato gun tutorials. In this particular case, the length of the video does matter. Rome was not built in one day, and the art of the potato gun cannot be fully absorbed and ingested from a two minute video.
The first is my favorite. There is real love put, even dabs into the history of RPGs and bazookas. As if excellence were not enough, he begins with classical music, and ends with a gallery of different potato gun styles and a detailed ways to design and apply desert camo.
Make Magazine and Bre teamed up for this one. It is less thorough than the one above, but a good tutorial nonetheless.
Sorry about the Lincoln Park soundtrack. A bit much, but very capable. This guys knows what he is doing.
Bill Gurstelle, Mr. DIY ballistics, takes an avuncular role in creating yankee ingenuity. God bless him. But he is a steady hand in this category.