Create a BP actor called BP_Projectile
Add Sphere mesh and Projectile Movement components
Set pojectile speeds as follow:
Go to 3rd person BP, viewport add arrow called projectile spawn post
adjust its arrow height to chest level, a bit in front of character
Event graph
Back to Projectile BP, make the sphere as the scene root,
in projectile movement, tick Should Boune (to let bullet interact with object)
The setting above will make scale has no effect on bullet size
To change bullet size, go to 3rd person event graph
break the Spawn Transform, and R click, split struct Pin
Repeat on World transfrom node
change scale as below
Optional (not work for me):
Create projectile damage/destroy:
Back to Projectile BP, sphere component
Add on component hit