When Joe shoots into the air, when the scene cuts to the bullet talking on the phone, the round is intact - casing, projectile and the primer cap - it should just be the projectile.
Cow tipping is a myth.
After Peter, Quagmire, and Cleveland almost die in Niagara Falls, they are saved by Joe. Peter then states that he thought he was going to die and that he pictured his own funeral. A cut away scene shows Peter's funeral with Quagmire and Cleveland in the service, and that wouldn't be possible since Cleveland and Quagmire would have died along with Peter.