Here is my setup
I too wasn't too keen on the idea of PVC + explosive propellant so decided to go metal + air. The 1" barrel is perfect for small potatos and smokebombs. 1/2" works great for acorns, m80's. 1/4" was for miniature arrows and firecrackers with an extended fuse. With the 1/2" barrel and the bike pump I was able to shoot a marble 4" into a styrofoam archery block from 20 feet. I have never felt unsafe using this setup. I have another piece that is not pictured that has a guage that is inserted between the valve and the barrel for when I connect it to the compressor.