Speed, weight, and shape of the projectile- along with the angle at which the barrel is raised above the horizonatal.
Weight, velocity, and shape of the bullet.
Factors include the angle at which it is fired, the speed of the projectile, its shape (ballistic coefficient) the air pressure and humidity.
velocity
velocity
The range of projectile is maximum when the angle of projection is 45 Degrees.
The first factors are: Speed, weight, and shape of the projectile. Speed will be determined by the powder charge used to drive the bullet, and the length of the barrel. Elevation angle (the angle at which the barrel points upward) will then increase or decrease the range based on the first three factors. For most firearms the optimal elevation angle is between 30 and 40 degrees for maximum range. Other lesser factors include the weather (wind, humidity, temperature) and altitude. Even the Coriolis Effect can play a small factor.
The half maximum range of a projectile is launched at an angle of 15 degree
Ignoring the effects of wind and air-resistance in general, maximum projectile range results when the projectile is launched/fired in a direction 45 degrees above the horizontal.
You are wrong
Suppose a projectile is fired from a gun, we know that "g" remains constant and as we use horizontal component of velocity in range sov0 also remains constant. Only sin2θ responsible for change in range. The range will be maximum if sin2θ has its maximum value that is 1.for maximum range:sin2θ = 12θ = sin-1 (1)θ = 90/2θ = 45 (degree)therefor if projectile is projected with the angle of 45(degree) its range will be maximum.
The horizontal component of a projectile's velocity doesn't change, until the projectile hits somethingor falls to the ground.The vertical component of a projectile's velocity becomes [9.8 meters per second downward] greatereach second. At the maximum height of its trajectory, the projectile's velocity is zero. That's the pointwhere the velocity transitions from upward to downward.
At 45° angle.