Muzzle break

From PyroGuide

Muzzle break - shell bursts just as it leaves the mortar, scattering stars and burning material in all directions near ground level. This is one of the most common shell failures because the rapidly changing pressure allows any weaknesses in the shell to be exploited by the lift gasses.

References

• Queensland Government : Queensland Code of Practice, Control of Outdoor Fireworks Displays - First Edition - 1 December 2003

A 100mm canister shell displaying a typical muzzle break. [1]