Y'all need to differentiate between velocity and acceleration. Speaking about the vertical plane, the acceleration is constant and downward (gravity), but the bullet starts with some upward velocity because your rifle barrel is pointed slightly upward from level. The highest point of the bullets flight is when it's vertical velocity is zero (the acceleration finally turns the initial upward velocity to a downward velocity).
If you fired your rifle barrel from completely level, you would need to be on a tower 27 feet higher (in this 1000yd Dasher example) than your target:
If you fired your rifle barrel from completely level, you would need to be on a tower 27 feet higher (in this 1000yd Dasher example) than your target:
