How can a shotgun shell with a powerful charge use a plastic case

Do you agree with Lloyd Austin's statement that it would be impossible to collect 17 million shells from all over the world? - Quora

Why do shotgun shells have brass or steel encasing the base while the rest of the shell is composed of paper or plastic? Is it necessary? - Quora

How can a gun be shot if it's plastic? - Quora

Is the 45ACP designed with insufficiently thin-walled shell casing, or in other words, is there too little room in the chamber for thicker and stronger shell casings? - Quora

Why are shotgun shells made of plastic? - Quora

What is the technique used to cut in half Nautilus shells without breaking them? - Quora

Seeing that shotguns use plastic shelled rounds, why don't guns generally use plastic shelled rounds? Would it not be cheaper and just as effective? - Quora

How can a shotgun shell with a powerful charge use a plastic case, but rifle shells have to be metal? - Quora

Has an invention ever been proposed regarding shell-less pistol or rifle ammunition? Meaning no brass steel or plastic casing. - Quora

When did the ammunition industry switch to using plastic shotgun shells from paper? - Quora

How do shotguns do so much damage? It's only small metal balls, right? - Quora

What is the wall thickness of a shotgun shell? - Quora