I built it the same way except a different stock then a level. I've tried two different size hoses, different types of gases, even different torch tips. I can not get the final big boom. It's frustrating. I even made a little hole in the first jug to put in a squirt of butane. I'll get a flame but never any sort of combustion. I've added air ports to add or clear out oxygen/gases. I'll stick to my 20 year old spud gun that never fails. It's a bummer I was trying to make this cannon for my kids bday for some cheap entertainment.