AR-platform rifles all have on thing in common: if you shoot them a lot, they need regular cleaning, and every so often, they require a little more attention.
The components of an AR have very close tolerances compared to something like an AK-platform rifle. This means that, when dirt does get inside and buildup from shooting accumulates, it can tend to cause problems in short order.
This is especially true for direct impingement ARs, which uses gas directly from the barrel forced into the chamber to propel the bolt backward after a shot is fired. In this video, Tom McHale shows you how to give your AR a good and thorough bath.