Thanks for the info. I went ahead and built my chamber tonight. I threaded in five automotive spark plugs down the length of it. I know that the spark is way off center using plugs, but they look cool. It's not nearly the most efficient ignition setup but I want my cannon to be aesthetically pleasin...

After searching through old topics, it seems that there is no definitive answer regarding the possible performance increase of multiple spark gaps vs. one well placed gap. The reason I am wondering is because I am thinking of building a cannon with several (6?) evenly spaced ignition points down the...