General
The American arsenal in Call of Duty is often regarded as the best and most balanced weapon set of the four factions. It is the second largest with 6 weapons.
M1A1
The M1A1 rifle is the weakest of all rifles in Call of Duty. Although it is weak it can be pretty powerful in the right hands, here are a few tips on how to wield an M1A1 correctly. First, this weapon is good at virtually all ranges, but not against MGs in close ranges and snipers at long ranges, so use mostly at medium-range. Second, aiming down the sight is always reccomended on this weapon because of its awkwardness when not ADS. It is also wise to refrain from switching weapons when not under cover because you have to fold the stock in and then bring out the next weapon, this wastes precious seconds and can easily leave yourself exposed to enemy fire or rifle butts. This weapon has a 15 round magazine and is of light-weight.
M1 Garand
Much different than the M1A1, the Garand is extremely accurate and powerful. The only draw back is does not have a good rate of fire and it can't be quick-loaded, you must use all 8 rounds. This is hardly a problem because it does not take much to reload this gun, just insert the rounds and you're set. Use at medium to long ranges. This weapon has an 8 round magazine and is of light-weight.
BAR
The Browning Automatic Rifle (BAR) is a heavy machine gun for the American faction. It has a 20 round magazine and is very heavy with a fairly quick rate of fire. The BAR is a support gun, meaning it should not be used in an offensive operation. Stay at medium to long ranges and use the sight while crouched (or prone). Reload often before you spot an enemy advance.
Thompson
The Thompson (Tommy Gun) is the American's one and only sub-machine gun. It has an extremely good rate of fire, is of light weight and has a 30 round magazine. Since this is a sub-machine gun that should be used at short ranges for offensive operations.