Video will come in ~24 hours, I want to see if I can do some more shots tomorrow/look for the dart and film its location relative to target.
That's what i'm thinking as the sound is roughly 0.75s after the shot and the fence is roughly 20m behind the target. We're looking at sub-150fps for sure. I'm surprised the camera picked up the fence hitting sound and not it bouncing back on to the driveway if it didn't stick. Perhaps it landed on a small patch of dirt or the sound is actually a neighbour/my brother (who was painting down by the house) reacting to the sound of the shot dropping/hitting something.Could it have struck the fence with minimal energy and just bounced off?
edit:
The projectile penetrated all four layers of the target, which are spaced apart, with a perfect exit hole so I assume it was still stable in flight. But by my rough calculations, the projectile should have also collided with the driveway as my driveway slopes up relative to target location. My rough calculations had the projectile making contact with concrete ~1.5m from the fence; perhaps my estimate was off by that amount.