I have the same problem. It's caused by the supressed beretta.
What I did was take it out of the storage, and then pop it in a trunk in one of my vehicles and it fixed the problem.
It basically creates one image of the gun PER item taken out of storage, so if you get 10 cocaine out of the storage, it creates 10 images in the storage, which sometimes can crash you and lagg you out like shit. This is reset everytime you close the storage chest.