Burning propellant ejected
Rocket went to top of tower and rear closure failed, spitting out all the grains plus the liner.
Ignition seemed fine and rocket ascended to just above tower where a loud pop sounded. Rear closure, liner and grains fell/were propelled out the end and the rocket continued coasting to about 500 feet before arcing over. Only one of the six grains burned up. Main deployed but didn't fully unfurl before rocket impacted. Damage is extensive. Case is a total loss and is carbon fiber rocket, save for a few parts.