List of COD MW3 Sniper Rifles

MW3 AS50 Sniper Rifle (unlocked level 22)
MW3 Barrett .50cal Sniper Rifle (unlocked level 4)
MW3 Dragunov Sniper Rifle (unlocked level 12)
MW3 MSR Sniper Rifle (unlocked level 66)
MW3 L118A Sniper Rifle (unlocked level 4)
MW3 RSASS Sniper Rifle (unlocked level 44)

Sniper rifles are the kings of distance, and in COD MW3 they are also the kings of the one shot kill. No other weapon offers the accuracy and deadliness of sniper rifles at extreme ranges.

Sniper rifles are either bolt-action or semi automatic, and have some of the slowest fire rates in MW3. Generally speaking, the bolt-action rifles (L118A and the MSR) are more powerful than the semi-automatic sniper rifles (AS50, Barrett .50cal, Dragunov and RSASS). Also, the sniper rifles have established one shot kill zones, generally from the lower torso on up, although some require a shot in the upper torso on up and one of these babies requires a headshot for a one shot kill.

Which Sniper Rifle Requires a Headshot for a One Shot Kill?
The Dragunov requires a headshot for a one shot kill.

Which Sniper Rifle Has the Largest Mag?
The Dragunov, with a 10 round magazine.

Which Sniper Rifle is the Deadliest with One Shot?
IMO, the MSR is the deadliest for a one shot kill.

Which Sniper Rifle Has the Highest Fire Rate?
The Dragunov has the highest firing rate of all of MW3′s sniper rifles.