Problem with parent animations (Blender to Unity)

I’ve been searching for weeks for a solution to this problem, and I’ve found nothing, I seem to be the only person on this planet that has ever had this problem, and I’m becoming pretty desperate now.

I have 2 objects, with a separate armature each, a gun, and 2 arms. I want to parent them together in a way that would work with unity, I would’ve thought using the “ChildOf” constraint would work, but apparently not, I can’t get it working, the animations end up going WAY in front of the object it’s parented to.

I tried using empties, didn’t really get any further with that.

I tried parenting the gun itself with the bone on Unity, and that worked fine! However, I imagine once I get to animating the Shotgun and Machine guns I’ve also modelled, it would be pretty tricky reloading and using any animation that involved the other hand.

So is there a way to parent armatures for an animation in a way that would work with unity? Or could someone give me a tutorial on it?

If you use the ChildOf Constraint, you have to ensure that your constraint values have keyframes at the start and end of the animation as well. Even if nothing happens.