Here again, I find myself dispelling a myth circulating around various shooting circles. This time I will be dealing with the basics of how to clean a Marlin .22 rimfire rifle, but first the crap going around that all these new, and even some experienced shooters are buying into. It goes something like this: "If you have a Marlin rimfire, don't ever clean the barrel until it gets so bad that your groups open up, since Marlins don't aren't accurate if they're clean. When shooting a new brand or style of ammo, shoot at least 100 rounds before checking accuracy so the barrel will become stabilized for that particular round." That is pure and utter B.S. in it's entirety.
The Marlin rimfire rifles are extremely accurate right out of the box, in fact they are generally as accurate as custom rimfires costing hundreds of dollars more. What Marlin has done is give the .22 caliber barrels 12 lands and grooves instead of the customary 6, and it works splendidly. Just like any other gun though, one must find through trial and error what particular fodder that his/her particular rifle prefers.
Have the laws of physics been changed specifically for the Marlin .22's making them different from all other guns? Point of fact is, all rifles perform their best and shoot most accurately (when using the proper ammunition that the particular gun shoots best) when the barrel is clean. No gun shoots better when it's barrel is dirty, not grungy, not fouled with copper, lead, plastic, powder, carbon, or other gunk.
Essentially what is happening is as one shoots, the barrel becomes fouled with carbon, unburned powder, lead, (sometimes copper) and bullet lube. As the barrel becomes fouled, the interior dimensions obviously change, becoming tighter and tighter, which can make some ammo fit the bore better for a short time, making it seem accurate, until the barrel becomes so gunked up that it starts sizing the bullet, and that's when accuracy really starts to take a nose-dive. Some rimfire shooters, when testing ammo, don't clean the barrel between ammo changes, so they aren't really going to find out what shoots best in their rifle. They think they are, but in essence all they are getting is false results based on a barrel that is getting dirtier and dirtier, instead of giving each type of ammo a fair shake with a clean barrel free of fouling.
I don't know about you, but I don't want to shoot a particular bullet at least a hundred times before hoping it starts shooting more accurately. When it comes time to clean, I don't want to have to shoot another hundred or so rounds to refoul the barrel so it will shoot tight groups again. It just sounds ridiculous! I want a bullet that shoots as accurate from the first shot after cleaning until the shooting session ends and I clean my rifle again. I expect that from my centerfire guns, and my rimfire Marlin is no different.
So don't listen to the "don't clean your Marlin" crowd, they're spouting total nonsense.
How did the rumor get started? A famous gunwriter once wrote (wrote several times actually), that with modern non-corrosive rimfire ammo, cleaning a rimfire barrel can do more harm than not cleaning it. Point of fact, if cleaned properly, it is not damaging to the rifle. What is damaging is cleaning your rifle from the muzzle instead of the breech, without a rod-guide, which can damage the crown. A cheap aluminum rod can collect grit and become embedded in the rod, scratching the rifling. Over use of abrasive and corrosive solvents can lessen the life of a barrel. To fix this though, use the proper products. Use a one piece stainless steel rod, and if you must clean from the muzzle, use a rod-guide. Use non-abrasive and non-corrosive solvents. Follow proper cleaning procedures recommended by the manufacturer. Another point to consider, non corrosive or not, powder fouling still attracts and holds moisture which can cause rust and pitting. The only thing standing between that moisture and your barrel is a little lead fouling, maybe.
My main point, for those of you who got lost in my rambling, is this: Buy a few boxes of several different types of ammo for your rifle. Clean your barrel when changing ammo, so you are starting off on even footing with each new brand or type of bullet. This will be the proper way to tell which ammo your rifle prefers. When done shooting for the day, clean and lubricate your rifle thoroughly before storage. Once you find what ammo your rifle likes best, you can rest assured it will perform admirably from the first shot out of a clean barrel until the end of the shooting session.