AutoTek 51 RSG Sniper Sentry

The Autotek 51 RSG Sniper Sentry is a tool that deploys a fully autonomous tripod-mounted perimeter defense system that holds a moderate amount of ammunition and can be placed on the floor or on objects depending on the tactical situation. The Sentry Gun is able to identify friend from foe, which allows team mates to walk safely within its cone-like range, as long as there are no enemies detected in it. However, if an enemy comes within range, the sentry will fire regardless of player presence and damage allies if they are in the way. Use with caution.

The cone of the Sentry Gun has 3 colors that visually communicate the status of the gun to the players:
 * Green : Sentry is active, ammunition is available, and scanning the area for targets.
 * Red : Sentry has identified an enemy/enemies and is engaging the target(s).
 * Grey : Sentry has run out of ammunition and is in idle mode. All functions ceased until further action is taken. Additionally, the Sentry will emit loud beeping sounds as well.

The Sniper Sentry fires powerful single rounds with a low rate of fire.

Like all version of the sentry it can be used to buy time for players doing scans or as additional firepower against enemy waves.

This sentry comes with longer range but less ammunition and lower rate of fire than both the burst or auto variants. It can kill the small basic enemies and Chargers in a single shot; larger enemies like the Big Striker in less than five shots. Scouts can also be killed in one shot. However, since the sentrys shot is not guaranteed to hit, it is unadvisable to try this, since a missed shot is going to trigger the Scout as well as the entire room. The biggest weakness of this sentry is the low fire rate, rendering it unable to fire if enemies can run past it quickly. This sentry also requires a few seconds before starting to fire. If enemies break line of sight with the sentrys scanner even for a short time, this timer will be reset. This also applies if enemies are spread out to far and reach the sentrys area of effect one after another. A steady flow of enemies and a clear line of sight (in long hallways or behind closed doors) greatly increases this tools effectiveness.

It was released in the extension of Rundown 004.

Pros

 * Adds direct firepower to the team.
 * Takes advantage of the sleeper's weak points if shooting in the back or the head.
 * The gun's targeting scanner can warn on where enemies are coming from.
 * High precision resulting in few missed shots and less friendly fire.
 * Long range.
 * Particularly effective against large enemies.

Cons

 * Requires constant tool resource packs to upkeep.
 * A badly placed sentry will be useless (enemies running behind or past it).
 * If enemies are moving side-to-side the sentry has issues tracking them, resulting in long pauses between the shots.
 * Can only fire at targets in front of the gun.
 * No crowd control.
 * Very low rate of fire.