Instead of using a ball valve or other such contrivance to dump air directly from a reservoir into the chamber of this PVC air cannon, [Ben] is using a much more clever design. This is a barrel ...

In a groundbreaking discovery, archaeologists have unearthed a bronze cannon in Arizona, directly linked to the legendary ...

Of course, you will also need to figure out how to use these barrels to reach the letters and puzzle pieces if you want to 100% Canopy Cannons. Here is where all of these collectibles can be found.