Try to find rigid cardboard tubing such as the tube from a wide roll of aluminum foil, which is thicker than most cardboard tubes but has a smaller diameter. You can also use a toilet roll tube, which is flimsy in comparison and a lot wider. A narrow tube will give better accuracy than a wider tube.;
, A craft knife will also give a nice clean cut.
 It takes time and patience but pays dividends if done this way. You need to slide the balloon neck over the tube till only the "bulb" portion is at the end of the tube; then, roll the excess back on the tube; at some point it will stop because it will be extremely tight on the tube and secured.


Roll on all the neck of the balloon onto the tube. If there is any amount of the neck not rolled onto the tube it will constrict under tension and cause a block; the projectile will simply 'spit' out because it hits the constriction on the way out. Ensure only the 'bulb' of the balloon is at the end of the tube.



BBs are ball bearings, and those sold as BB 'ammunition' are, in fact, slight rejects that fall outside stringent tolerances; often failing by a few millionths of an inch. Precision ball bearings are expensive and unnecessary for ammunition.
BBs are much more accurate because of their even surface and will project further than uneven chippings or loose stones. Small stones, because of their sharp edges, are likely to rupture the balloon sooner. Although the cost is minimal, it can take a long time to replace.
 With the other hand, use your finger and thumb to grip the projectile through the balloon and then pull back to your desired tension. Start off short and work up to greater tension as you become more confident and have some control of its trajectory and begin to achieve better accuracy. Release, and the balloon will snap back to shape and the BB/projectile will shoot out through the tube.
Choose a suitable tube.
Cut a 6" length of this tube.
Choose a balloon that's a tight fit on the tube without having to cut the neck from it and slowly work it onto the cardboard tube, gripping it with your fingers and going around the tube to slide it on evenly.
Projectile: To load the sling-shot drop a BB or small stone into the tube and into the balloon.
Hold the cardboard tube with one hand.
{"src": "wikihow-all_test", "title": "How to Make a Tape Roll BB Shooter"}