These are the common joints I know
Images:
Root
mountNode
muzzleNode
ejectNode
<insertnamehere>Node
Players:
Root
mount0 to 8
cam
eye
All others are up to you
Vehicles:
Root
mount0 to 32
hub0 to n
cam
eye
<insertvehiclenamehere>100 (For LOD fixing. You may need to assign all non-moving parts to this joint)