Silencer

A suppressor, often also referred to as a silencer, is a device fixed on the end of a gun's barrel to suppress, hence the name, the sound of a shot going off from the weapon. In real life, suppressed weapons are generally still semi-loud, but they also bring advantages such as greatly reduced muzzle flash, and reduced recoil. They reduce the sound of gunfire by allowing the rapidly expanding gases from the firing of the bullet to be temporarily diverted or trapped in a series of hollow chambers, known as expansion chambers. The trapped gas expands and cools, and its pressure and velocity decrease as it exits the chambers. Suppressors can fire super-sonic ammunition but this wears out the suppressor very quickly and is not as quiet as using sub-sonic ammunition.

In-Game
In Call of Duty 4, the silencer can be used on pistols, assault rifles, or sub-machine guns. When a player fires a weapon without a silencer, they will temporarily appear as a red dot on the mini map to enemy players. Firing a silenced weapon will not cause the player to appear on the mini map in this fashion. The silencer also reduces shot loudness, muzzle flash, recoil and effective bullet range. Note that a silenced weapon grants no amnesty from the UAV Recon.

The "invisibility" afforded by the mini map is invaluable for flanking or ambushing. Even when enemies are alerted to your presence, they must either call a UAV or make a visual in order to locate you. Along with the reduced shot loudness, this makes it much more difficult to locate, and furthermore track, your movements.

The major disadvantage of the suppressor is the reduction in damage over range. Damage over range is reduced to about 70% of its original value for SMGs and pistols, and to less than 50% for assault rifles. It should be noted that at 1000 range and beyond, bullets from a silenced assault rifle will be dealing their minimum damage, while an unsuppressed assault rifle will still be dealing maximum bullet damage. This emphasizes the use of suppressors as a close to mid range attachment.

Despite the range penalty, powerful and loud weapons such as the AK-47 or the M14 can become somewhat more manageable with a silencer in certain situations. Such weapons are often plagued with being a combat magnet from the range at which they can be heard firing. With a silencer, they become particularly devastating at mid range due to the stealth and sheer power.

As the only thing that can reveal a player using silenced weapons is a UAV, the UAV Jammer Perk is an obvious choice for those wishing to take the pure stealth option. A silencer + UAV Jammer class can easily sow chaos in the rear lines of the enemy ranks. Taking a silencer without a UAV jammer is more risky than taking a UAV jammer with no silencer. The player may suddenly be revealed when using just a silencer. Therefore, on larger matches, it's preferable to either take both or just the UAV jammer, as a well timed ambush can kill 3 or 4 enemies in seconds, negating the need for a silencer as there are no enemies there to kill you. Alternatively, bring a silenced pistol, which could allow for a couple of easy kills without alerting the enemy team.

The silencer attachment is unlocked at 75 kills (the second Marksman's Challenge) for SMGs and assault rifles. The attachment is automatically unlocked for pistols when the pistol itself is unlocked.

In singleplayer, it is mounted on the USP in All Ghillied Up, One Shot, One Kill, Ultimatum, All In, No Fighting In The War Room and Mile High Club, the MP5 in Crew Expendable, Ultimatum and Mile High Club (where you start with a special MP5 SD with integral suppressor), the M4A1 SOPMOD in a majority of MacTavishs missions, the M21 in Blackout and All Ghillied Up and the P90 in All Ghillied Up. (Note that this is the only suppressed or red dot sight-using P90 in the singleplayer portion of the game, the P90 SD.)

Call of Duty: World at War
Working in the same fashion as their Call of Duty 4: Modern Warfare counterparts, the Gewehr 43 and all SMGs except the PPSh-41 can have suppressor attachments to them. Oddly, the Gewehr 43 with the suppressor attached will reload when you exhaust the entire clip the same as if you are at partial magazine. The reload at partial magazine is hastened so that it takes the same amount of time as a normal mid-mag reload, but if the entire magazine is spent it will reload as slow as it normally would. Enemies will have difficultly finding your exact position if you catch him off guard. Missed shots are also less detrimental with the suppressor, as the enemy will have more difficulty telling where the shots came from, however they will still hear the crack of the bullets flying past them and see the tracer shots. The Flash Hider functions similarly to the Suppressor but has slightly inferior noise reduction and is available on the rifles instead.

Unlike Call of Duty 4, pistols do not have suppressors and they cannot be unlocked.

Weapon Combatibility

 * Gewehr 43
 * Thompson
 * MP40
 * Type 100

NOTE: Other weapons have the similar device called the Flash Hider.