Legal Question in Criminal Law in Michigan

Not unless you want a murder charge. That is not self defense if they are not pointing it at you.

Maybe. Every shooting will be judged based on the actual circumstances of the case. To say that every time someone raises their shirt to display a gun you would be justified in shooting them would be wrong. As a matter of fact, in most cases, that would not justify a shooting. If there was more to the story, such as the person threatened to shoot you, raised their shirt and then reached for the weapon, you MIGHT be justified in shooting to defend yourself. It really will depend on the specifics of the actual case. There is no way to tell you ahead of time other than you really better make sure that shooting the person is the last and only resort to protect yourself. Otherwise you could spend the rest of you life in prison.