DR9 Firework Rack Build and Test Firing

I wanted to build new firework racks for new DR9 mortar tubes I just bought. I needed some dedicated racks for smaller diameter reloadable shells. I came up with this design by borrowing the main idea from my old 55 shot racks. They were actually the first racks I ever made. What I like most about this design is the ability to accommodate different fireworks just by changing the plywood inserts. I cannot vouch for the safety of this design because I have not had a tube failure on this style of rack. If you don't feel like this is a safe design then just don't build it. Should I ever have a tube failure on one of these racks I will share how well they hold up.
Music:
Jozeque - Flexed
Jozeque - Mage