Given the harsh use MSRs are usually subjected to, it’s a wonder they run as well as they do. Keeping an MSR in top shape isn’t hard, though. Just remember the handy acronym MEAL.
The magazine is one of the weakest parts of any semiautomatic. It can get gummed up with dirt and debris, or the feed lips can get bent when they are dropped to the ground, causing cycling failures. Don’t join or “marry” your magazines. They will be more prone to damage if you do. Magazines are easily replaced, so discard them if they’re faulty.
Potential problems here include a weakened extractor that can break, weak extractor tension, or a dulling of the extractor that can lead to cycling failure. Should you experience extraction failure, most notably in the form of a stuck cartridge in the chamber, your most likely cause is the extractor. Either replace the spring or, if the extractor is no longer sharp, replace the entire unit.
Some shooters think ammo is a good place to economize. It isn’t. If you buy subpar ammo, you can expect to have problems with misfires and other issues. It comes down to quality control. Good ammo is manufactured with accurately metered powder charges, bullets that are seated correctly, quality cases and sealed primers. With poor ammo, these aren’t a given. Stick with ammo from reputable makers.
Lubrication is a must for MSR rifles—but where should you put it and in what quantity? The most critical place for oil is the bolt. A generous dollop on the bolt body and a lighter coating on the firing pin is what I recommend. Conversely, keep the workings of the trigger and the interior of your magazines free of lubrication. Synthetic motor oil is great for use on MSRs. One key advantage is that it doesn’t contain carbon, which can lead to nasty fouling, and in a heavier weight, such as a 10W-50, the oil tends to stay in place, which is an advantage.