Why are shotgun shells made out of plastic while rifle shells are

Shotshells: Interpreting the Numbers on the Box

How do shotgun shells work? - Quora

Rifle vs Shotgun? First Time Gun Buyer

Back To Basics: Cartridge Cases

Why are shotgun rifled slugs have little weight compared to buckshot? - Quora

Why is your rifle made mostly of plastic? - Quora

What are the basic Parts of a Shotgun Shell?

Why are shotgun rounds just metal balls? - Quora

What are some military grade shotgun shells? - Quora