Knex Heavy Cannon
I just finished my heavy cannon. It shoots a large projectile a distance of at least 50 feet with 4 rubber bands, but i could easily get more with more rubber bands and a better angle, if you look in the pics you'll know what i mean. It was deigned to look like an actual cannon but it turned out to be for performance. I probably will post, so don't forget to rate, comment, and subscribe.
https://www.instructables.com/id/Knex-Heavy-Cannon-Instructions/
https://www.instructables.com/id/Knex-Heavy-Cannon-Instructions/