Hello,
isTrigger would be more for a zone Player enters and barrel explodes or starts a count down.
I would use On Collision Enter. This works if atleast one gameObject have a rigidbody component, the barrel or a baseball bat/a bullet could have a rigidbody.
Hitting the barrel, it would catch collision float for example and subtract from Health float in fsm. Compare Health float and if its 0 then explode
