If "an object travels that is shot horizontally at a velocity (v)", any object shot at velocity (v) will travel the same horizontal distance (neglecting air resistance). The horizontal component of travel experiences no acceleration so the initial velocity (v) remains constant.
The vertical component is experiencing a downward acceleration due to gravity. This acceleration is the same for any mass object so they reach the ground together. Like dropping a basketball and a medicine ball at the same time - they reach the ground together.
If the mechanism that shoots the first object remains the same, then shoots a larger mass object, this second object will not have "velocity (v)" to begin with. Is this what you mean?