The M1A1 Carbine is a gun that is unlocked when you are level 65. It is part of the rifle class and is not automatic. If you reserved Call of Duty 5 at Gamestop, you can use this gun at any level. However, it will only be in a default class and cannot be used in your custom classes. The only available attachment for this weapon is a suppressor. The M1A1 is viewed by most players as the best rifle in the game. This is mostly due to its highly consistent accuracy that, when coupled with the weapon's superior firepower, gives it a large advantage against most other rifles. Unfortunately, since you get it so late in the game, most players never get a chance to fully experience the M1A1 at its full potential.