Interesting question.
"Bangsite (tm)" is basically calcium carbide, when mixed with water creates acetelyene gas.
Are you worried about being cited for using it? As long as nothing leaves the barrel (except noise and flame) you may wiggle out of many local ordinances that might be used against you. Note that many regulations which are based upon the Uniform Fire Code (UFC) (or derived NFPA sections) have an excemption for "small" noisemakers (party popers and the like); if challenged (like I was) simply offer to build a "bigger" noisemaker to demonstrate the legal ambiguity in determining what constitues "small. " (Note that there still may be several misdeamenor "nuisance" ordinances that may be used against you... )
To Wit: Use ABS plastic pipe, heavywall (sch. 80) 4" diameter. Use a cleanout tee, glue slip x thread adapters on all 3 sides. Place very short pup with clean-out plug on the bottom, threaded plug on one side, and an 8' long barrel on the "discharge" side of the tee. Epoxy in a short 3/4" drop piece of PVC with a threaded cap on top. In the center of the rear threaded plug, mount a Coleman latern spark ignitor. Visit any army surplus store (or camping outlet) and buy a can of Calcium Carbide, in pellets form.
Fill with bottom of the tee with fresh water. Drop in a few pellets of calicum carbide through 3/4" feed tube into the water chamber. Repalce 3/4" cap. Point the barrel in the direction of on-coming wind, this will help stir up the air in the barrel and acheive a stoichemetric mixture. Give it about 20 to 30 seconds. Shout "READY" - "AIM" and "FIRE" and let it rip. You should hear echoes off of any hills up to 10 miles away.
CAUTION! ABS PIPE IS FRAGILE. USE AT YOUR OWN RISK! DO NOT EXPOSE BARRELL TO ANY BACK PRESSURE. DO NOT ATTEMPT TO USE FOR LAUNCHING ANYTHING! NOISE CAN CAUSE PERMANENT HEARING DAMAGE-DO NOT POINT TOWARDS PEOPLE, PLATE GLASS OR OCCUPIED STRUCTURES! DO NOT USE INDOORS!