Just add a delay after Event Begin Play inside your Projectile Actor. So Instead of using distance to measure how far the projectile has travelled, use time. For Example, if you set the delay to 2 seconds, the projectile will have travelled X distance during that time. So by adjusting the length of the time variable, you can adjust the travel distance of your projectile. When the delay ends, spawn emitter at location (Explosion) and then destroy actor.
