To clean the Stevens 320 shotgun, ensure the shotgun is unloaded and pointed in a safe direction, disassemble the gun by removing the magazine cap and sliding the barrel forward off the slide arm, Tap out the trigger guard pin located just above the trigger to remove the trigger assembly, and then remove the slide arm and bolt assembly.The cleaning procedure is essentially the same as for other pump-action shotguns.
A full cleaning of the Stevens 320 is recommended after every 200 rounds. Using the correctly sized brush, clean the bore by wetting the brush with a gun cleaning solvent such as Hoppe's Elite Gun Cleaner and pushing it through the barrel several times. Then, remove any remaining residue in the barrel by pushing through a cleaning patch soaked with a rust-preventing lubricant such as Break-Free CLP. If the Stevens 320 has a removable choke, unscrew it from the barrel, and clean it with a choke tube solvent.
The action should be cleaned and lubricated as well. Using a brush, clean any residue or dirt on the firing pin mechanism and the trigger group assembly. Then, apply a small amount of gun oil to any parts where metal touches metal. Re-assemble the gun in the reverse order, and apply a light coat of gun oil to the exterior metal parts of the firearm. Test fire the weapon using dummy rounds to ensure proper operation after reassembly.