Gun fire animation problems. Shell back to gun on play

Hi, I’m newbie.
I made an animation which firing gun, ejecting shell then making it disappeared after few seconds.
On animation panel, it works what I’ve expected. However on play(VR or Desktop), shell always back to gun rather than disappearing.
I’m stucked it.
How can I solve this?

How are you making the shell disappear. There are numerous ways this can be accomplished, by turning off the mesh renderer, animating its visability via shader, scale down to 0% on one frame and other techniques.

Research if - how you are making the shell disappear is supported in VR.