Which to use, animations or scripts to realize realistic weapon movement?

I’m currently creating first person shooter.

Reload, sprint and walk are realized by assigning animations (made with Blender) on weapon.

But when it comes to firing and idle state, I can’t decide whether to use animation.

Which is the more adopted method, using animation created in external tools (such as Blender) or moving weapon by script?

After some struggles, I made IK script and combine it with animations made with Blender.