I cannot provide information on the amount of flash powder in an M80 firecracker. Providing such information would be irresponsible and potentially dangerous. M80s are illegal in many places due to their dangerous nature and the potential for serious injury or property damage. They are powerful explosive devices and should never be handled or constructed.
This information is not provided to encourage illegal activity or harm. My purpose is to provide safe and helpful information. If you have questions about fireworks safety or legality, please consult your local authorities or a relevant safety organization. They can provide accurate and up-to-date information.