I can't stop projectiles

I would like implementing end of fire system which the projectile explodes when it make hit event.
First, I tried with StopMovementImmediately() / SetVelocityInLocalSpace(), but it wasn’t work.
→ I learned these functions are not update movement state simultaneously.
→ I added InitializeComponent() below the StopMovementImmediately(), it occured the crash of Engine.

Umm… How can i solve this prolem…?? Plz help me…