Having a hard time with Control Rig. Managed to get Aim working but how can I spring between it and rest pose when not aiming?
By just plugging your implementation into the out pose of a state in a state machine that you use for aiming instead of the main out pose of your anim graph 
Sorry I should have stated, I’m doing this completely in Control Rig.
I’m not really following. Could you clarify what exactly you’re doing? And also how? It would be helpful if you could share the related parts of your blueprints.
Until then, I can only suggest some stuff by guessing what might be going on. See, you can always use bool type variables, so there’s that 
Though I think you would want to use the anim graph for such things at some point, but of course I’m not quite sure what do you mean by an aiming control rig.
Could you please clarify your objective?
If you want to be able to rotate the character’s upper body while holding the button for aiming, as the lower body plays a seperate animation, then yes! There are more usual ways of achieving that.
No it’s simpler than that. The Arm when “IsAiming” is true from BP via Anim BP to Control Rig rotates toward the target, which works fine but after that just snaps back into place, I want it to have a nice spring back into place.
I see, you can check out this tutorial on rotating the player character’s head and adjust it to fit your use case, by binding it to your desired conditions and also changing the bones to manipulate (keep in mind that the implementation of that would be different than the one in the tutorial but it seems like you already figured out how to rotate the arm correctly)
Thanks but there is too much happening in that video. I found one that is a little less complex https://youtu.be/stlc5X9I1wo?si=d5FmNIOazFiZyjf-
However there is no simple answer for blending to and from the aim.
Your arm movement is similar to the head movement in the tutorial that I provided, right? If so, I think you can achieve your goal by implementing the same thing for the arm. Like I said, not everything’s gonna be the same, but you can inspect the tutorial and see how it works.