Below CCI 400 primers fired in a AR15 rifle, the primer cups are too thin for this type over gassed rifle.

And the anvil has been pushed out the hole in the primer by chamber pressure.







Moral of story, know thy rifle and more about the correct primer to use in your rifle.
And if your SKS goes full auto you will need to use "Shout stain remover" on the brown stains in your underwear.