The Assault Rifle is a good weapon at medium range, but it will sometimes jam (the avatar will look like it has glitched the gun). To unjam the rifle, you must reload another weapon. If in quickmatch and you are playing with the AR only, you can also pause and unpause the game. It is very annoying, but it works.
When reloading the AR, it is best ot take cover or move around a lot until a new clip is inserted.
The standard human assault rifle issued to all human soldiers combines speed and power to make it one of the best automatic rifles around. While not as powerful as the Magnum T2, it delivers 15 rounds per second with a clip size of 30. It may not seem too powerful, but it's deadly in the right hands.