Here is a legacy project that goes way back. It is a potato gun I made with the help of my dad. It was constructed out of ABS. The sections were made from drops that were in the store available for purchase. I believe it was 3 inch chamber to a inch and a half reduction. Then we put a threaded end on with a flint striker. It has had a lot of use over the years. I believe we made this when I was in middle school. I still remember him helping out with making a light bulb for a science fair project in grade school. He hooked it up to a car battery and set the grass on fire. It did win most scientific though.
MadMatMax 