A few paragraphs for questions about projectiles and shell casing, law homework help

Rifling lands and grooves in the barrel of a firearm can impart both class and individual characteristics on a projectile. Subsequently, both class and individual characteristics can be found on the shell casing.

Please respond to the following prompts:

• Discuss the striations and the individual and class characteristics of projectiles. Include what may prevent a firearms examiner from making a perfect match.
• What items impart marks onto the shell casing?
• Discuss the individual and class characteristics of the shell casing.

Please have references as well as in text citations for any outside resources.