How do you take down and clean a Mossberg 340BB 22cal rifle?

Answer 1

Make sure that the rifle is unloaded and remove the magazine. Remember where you put it, because those magazines are very difficult and costly to replace.

Turn the rifle over, with the barrel horizontal, upside down, trigger guard up.

Using a screwdriver (or coin) that fits, carefully remove the large screw that is a few inches ahead of the trigger guard.

At this point, the entire barrel and action will lift out of the rifle. Set the stock aside, being careful not to lose the screw that holds the barreled action in place.

While it's out of the wood, open the bolt, close the bolt, push the safety off and pull the trigger. (Make sure it's unloaded, and still point it in a safe direction.) Watch the action of the trigger/hammer. Note how when the trigger is pulled, a rounded piece on the bottom, that functions as the hammer, rotates when the trigger is pulled. Open the bolt and pull the trigger again. Note how the round piece moves. IF YOU HAPPEN TO PULL THE TRIGGER WHEN YOU HAVE THE BOLT OUT OF THE GUN, YOU WILL HAVE TO RE-COCK THE ROUND PIECE OR YOU WON'T BE ABLE TO RE-ASSEMBLE THE RIFLE! DON'T PULL THE TRIGGER WHEN THE BOLT IS REMOVED!!!

As you look at the upside down action, note the black plastic plug that closes the back of the action. Note that there is a small lever on the bottom of the plug. That lever pushes forward, while you pull it out. It's a bit awkward, but works. When you push it the right way, you'll be able to gently pull the plastic plug right out of the action. Set it aside with the magazine, etc.

Push the safety off. Now, a bit of care is needed here. DO NOT pull the trigger. Resetting it will be a pain- you have to rotate the hammer piece I mentioned above.

Put the safety back on. Now you can use a normal cleaning rod with brush and patch to clean the rifle. Check the trigger mechanism for dirt and clean it out. Same thing with the action plug.

Using a solvent like Gun Scrubber, clean up the bolt, then lubricate it and the trigger mechanism lightly.

Put the bolt back in, slide the plastic plug back in until it clicks.

Wipe off all the outside metal with a light coat of oil, especially where the wood covers the metal.

Carefully fit the action back into the stock, and tighten the action screw tightly, being careful not to scar the stock with a slipping screw driver.

If the receiver sight is in place, lightly lubricate the threads of the sight.

Wipe off the metal work with a light coat of oil, and go shoot a great little rifle!

With modern .22 loads, very little cleaning is needed. One of the members of our deer camp was a small bore shooter on the '88 and '92 Olympic Team. She said that they never clean the bores of their rifles- it causes more wear than shooting! However, the dirt and powder residue (and weed seeds, etc.) that end up in the rifle will gum it up. Clean the mechanism well, and make sure that the metal never looks dry. All it needs is the lightest coat of oil. If you care for it, it will last a couple more generations.