I have a 20 ga, my son has a 12 ga. We use mainly for duck hunting. Both have been opened up to take 3" shells...... this is doable because they are built like tanks. I know of one highly sought after custom gun guy.... especially shotguns..... who uses a model 24 12 ga for waterfowl. They shoot, they are built tank tough, and not afraid to take them afield.