[Autotune]

I'd wager any .357 bullet from any direction to the skull will kill you. Even if you are incredibly lucky and live through the shot, unless someone finds you immediately after, you'll still bleed out and die.

A quick google search could give you all the information you would need on the best angle to pull the trigger to your dome and what ammo to use.

There are plenty of other, more effective and certain, ways to kill yourself though. Guessing you are choosing a gun because you're actually afraid to follow through with suicide. Most people choose guns because you can hype yourself up to pull the trigger and possibly die in an instance, where as other means take planning and causes people to back out who really don't want to die.

Either way, good luck living or killing yourself... not everyone is cut out to live through this shitty world.