Here the steps to recreate the situation.
Create blueprint-based first person template project with starter content
Open first person projectile blueprint
Set initial life span to 30 seconds
Remove all code in blueprint
Add radial force component
Set radius to 40000.0
Set force strength to -50000.0
Set impulse strength to 0.0
Add another one radial force component
Set radius to 50000.0
Set destructible damage to 100.0
Add OnComponentHit node for collision component
Add fire impulse node for second radial force and connect it to OnComponentHit node.
Open starter content folder, then shapes and find Shape_Sphere mesh
Right click on it and select create destructible mesh
Open it
Set damage threshold to 50
Set damage spread to 0.0
Check enable impact damage
Set impact damage to 1.0
Set debris lifetime min to 20, max to 30
Check accumulate damage
Check world support
Check debris timeout
Set support depth to 2
Set minimum fracture depth to 1
Check enable debris
Set debris depth to 1
Set cell site count to 50
Click on fractures the mesh’s root chunk on toolbar(blue cube icon)
Save all
Place destructible sphere on level.
Try to shoot projectile near sphere and see what happens.
Then try to play with sphere sizes. When you will increase the size of sphere, you will see that you need to increase force strength to achive the same effect.