Hunting Rifle - Shooting + Shell Ejecting

I modeled the Hunting Rifle from Fortnite. This rifle is capable of shooting TOY bullets, shell ejecting, and has a bolt action feature.I will lik here videos showcasing the gun and showing how to assemble it's pieces. The extra compontents required other than the 3d models are 3 rubber bands (+1 for every bullet) and a common Pilot pen spring. For it to work, the spring must have the following dimentions: D =  6mm, d = 4mm, L = 19mm. Insert the spring in the pause of the BoltUpdated model (