Playing a bolt cycle animation when a grenade launcher is fired

[lolmartsecurity 10]

I'm back again with another silly question. This time I need to get a way to play a bolt cycle animation when a unit fires a grenade launcher. Basically, I'm working on an OICW-type weapon with a bolt-action grenade launcher module. I need to get the unit using the weapon to play an animation only after firing the grenade launcher. Is there any way to do this efficiently, or should I just leave it ArmA II style and just have the bolt move itself?