What causes it to rotate is the rifling in the barrel. What causes it to continue to rotate after it leaves the barrel is centrifugal force.
Projectile expansion or projectile tumbling.
An entry and exit wound generally refer to the two parts of a bullet wound that passes all the way through. The entry wound is where the bullet hits something, and the exit wound is where the bullet exits after passing all the way through.
you just exit and it will save itself
clockwise
When gunpowder detonates, it creates a gaseous byproduct which expands very rapidly. The expansion of this gas is what propels the cartridge through the barrel.
is wider on the exit side
Assuming the bullet is fired from a gun, the bullet will move out of the bore with a high velocity and will immediately begin falling and decelerating. If the bore is rifled, the bullet will also rotate on its long axis (providing stability in flight).
False
If you mean the spiral grooves inside of a rifle barrel- those are the lands (high spots) and grooves (low spots) that make up rifling. The bullet, being softer than the steel of the barrel, is pushed into the rifling when fired. The lands cut into the outer edge of the bullet, gripping it, and causes the bullet to rotate with the spiral. This rotation causes the bullet to travel in a straight line as it passes through the air- and is much more accurate than a smoothbore (no rifling) barrel. Ever notice how a football spins when a pass is thrown? Same thing.
the way it tilts on its axis
Rotate
This all depends on the caliber and the particular load but, yes. The bullet can be stopped by bone or ricochet vertically.