Please add some content to this page to help people out.
There are more guns than are currently displayed, the list is not yet complete.
SMGsEditType 05 SMG: A weak, inaccurate SMG with a high rate of fire. Given at the start of the game.
MP5: Weak but accurate SMG with low recoil. Produces less aggro than most weapons. Costs $15,000
P90: Average damage with low recoil and medium accuracy. Fixed magazine capacity to 50 rounds per mag. Unlocked in Chapter 2 Vertigo when sniping the guys who are holding hostages
TDV .45 SMG: A powerful SMG with average accuracy and high fire rate. Cost $35,000
G36C: All-purpose assault rifle. Given at game start. Places many shots on target easily. Used by many 40th Day mercs and can be found everywhere for use as a temporary weapon.
AK-47 : Hard-hitting assault rifle with low accuracy, slow fire rate and harsh recoil but decent handling. Cheapest assault rifle available. Cost: $1,100. Can be modified to reduce recoil to a medium level while maintaining power.
QBZ-03 : All round assault rifle with good damage and accuracy, but the incredibly fast fire rate makes it very easy to empty the magazine. Cost $12,000
M4 : All-purpose assault rifle. Average damage and very accurate, low/medium amount of recoil.
FELIN 2C : Highly Accurate but has average damage and handling but high fire rate. Unique weapon parts when in customisation.
SCAR-L: Highly accurate assault rifle with medium damage. High rate of fire. Initial rifle is extremely precise. Places most shots on target with greatest ease.
M416: All-purpose assault rifle. Very reliable, has medium Accuracy, Recoil, and high Power. Obtained by doing a bad morality choice early in the game, but is unlocked for purchase at the beginning of chapter 3. Very well rounded assault rifle.
AS-KR1: Unlocked by having a save game file from the previous Army of Two. The secondary weapon on this gun is a shotgun almost identical to the AA-12 due to same rate of fire and power. Can't be upgraded, but fairly strong and has a built-in scope. Cost $300,000. Built for looks, not performance.
Masterkey Shotgun : Front mount weapon, can be attached to assault rifles and the MK 6 Grenade launcher. Cost $30,000
Remington 870MCS: Pump-action shotgun, high power. Costs $2,100
FSB Shotgun : Pump-action shotgun, high damage and fair amount of recoil. cost $15,000 Best with shield in front.
HM shotgun : Magazine-fed, able to upgrade ammo capacity. Low fire rate (semi-automatic), Medium to High damage and medium recoil. Can be unlocked by stealing the weapons in chapter 2 Murray
AA-12 : Initially comes with an 8 round magazine, though the 20-round magazine is highly recommendable as you will find yourself reloading far too often otherwise.. Fire rate of 300 rounds pr. minute (fully automatic), High damage and low recoil. Costs $50,000
M249 SAW : A powerful but inaccurate heavy machinegun. Has decent recoil and high rate of fire, can be reliable in most situations but burns through ammo quick and comes with an atrocious reload speed. Cost $22,500
Type 77 : Given at the start. Very weak, takes many shots to kill. Small magazine and low power makes this a terrible choice.
Desert Eagle .44 : 12 round mag. Decapitates foes in one shot, unless they are utilizing a helmet, then it takes two.
G18 : Machine pistol, fully automatic. Weak, but automatic fire makes up for it. Burns though reserve ammo rapidly. Use as backup only. Can only be unlocked by having all good morality choices(Press A/X to kill, B/O to spare type choices) from the start of the story until the start of the Hospital, in the Armory. You will be notified if you have or have not had all good choices once at the Armory.
SVD : Decent gas powered rifle. Given at game start.
M110 KAC : Decent Powered rifle with fair accuracy and average recoil. Costs $9,500. Base gun gets one shot kills in most parts of the body.
VSS : Built in Silencer-Barrel. Low recoil, Accurate but low to medium Damage. Costs $17,500.01
M107 : Strongest sniper you can unlock via game play. Boasting a .50 Caliber round, this gun can detach limbs, explode heads, and penetrate armor. Given by letting Chin get the sniper rifle in Chapter 4: A Room With A View.
Grand Pinger: Unlocked by having a save game file from the previous Army of Two. Sniper that can fire explosives.
MK Grenade Launcher : six shot grenade launcher; about as powerful as a standard grenade. Costs $75,000
Diamond Encrusted Grenades : Same effect as same as standard grenade. Costs $100,000
RPG-7 : Powerful rocket launcher, most effective against super-heavies, cannot be modified except for the style. Costs $18,000
Riot Shield : ''Mobile Cover'', very useful but takes damage and eventually will break. Can melee and charge with it.
Gatling Gun: Very heavy gun that requires some hard work and time to spin.
Flamethrower: Has a very short range, almost requires you to be on top of the enemy. Fire in quick bursts.
GenadeLanucher: Can be dropped by a Heavy Grenadier.
Shotgun: can be dropped by a Heavy armor With a shotgun.