Shoot ranged items and Summon mobs with velocity Problem

I know it has been wonderful since Mcreator add shoot custom ranged items and Summon mobs with vx/vy/vz. But, can we shoot ranged items with different directions, not just in front of us? Or if this is not possible, why cant we summon custom ranged item bullets with velocity? I mean we can summon many entities, include arrow but I can find custom ranged items' bullet ?