Overwatch Standard Issue Pulse Rifle

The OSIPRs are also equipped with an energy orb launcher that fires Combine energy orbs. These orbs will bounce around and disintegrate any organic enemy on contact, and will continue to ricochet around until the energy dissipates and the orb detonates harmlessly.

Overview

The Overwatch Standard Issue Pulse Rifle is a weapon manufactured by the Combine Empire, derived from modern human assault rifles for use by the Transhuman Arm of the Overwatch. It is very accurate at short and medium ranges and is best used in short, controlled bursts, since when firing continuously, it tends to wander due to the recoil. For added control, similar to assault rifles it descends from, it is equipped with a pistol grip.

Construction

The rifle is manufactured from the same alloy most Combine technology is produced from, which guarantees durability and reliability in the field. The design is derived from modern human assault rifles (in this case apparently the FN Minimi, manufactured in Belgium), however, due to its different working mechanism, it varies significantly. It's based on the Combine energy pulse technology, which is also used in Hunter-Chopper, Gunship and Dropship Personnel Carrier cannons, sentry turrets and APC machine guns as well as Hunters and Striders. The forward part of the weapon contains all the working mechanisms of the rifle - the magazine feed, the firing pin for the energy plugs, the energy barrel, the orb launcher and its firing mechanism.

• The energy barrel is suspended over the orb launcher via a short metal beam, additonally fitted with an armor plate for protection. Inside, the energy barrel is laid with resistant material, which prevents the exploding energy from ripping the barrel apart and additonally helps direct the blast.

The barrel is additionally outfitted with a set of grips locking the plug in place.

• Magazine feed - the rifle utilizes special energy plugs, which are stored in Combine designed ammunition cartridges, resembling thin drum halves. Each drum is outfitted with it's own plug loading mechanism, as a measure to improve the weapon's reliablity and minimize the amount of weapon's firing mechanism parts. The ammunition cartridges are mounted into the underside of the weapon and locked in place.
• The firing pin - the firing pin, unlike human assault rifles, does not operate within the rifle's body, but instead operates outside of it. It is also significantly longer and larger than human pins, resembling a long spike. This design is required for it to effectively detonate the energy plugs.
• The orb launcher is located directly underneath the energy barrel and in front of the plug cartridge. It is basically a tray outfitted with an OSI firing pin, large enough to detonate the charge and release the orb.

Working mechanism

The OSI Pulse Rifle posseses two fire modes: automatic energy pulse fire and orb launch.

• Energy pulse fire (fig. 2a) - by pressing the trigger, the firing pin is released and hits the detonator of the energy plug. This action releases energy stored within the plug. In normal conditions, it would burst outwards in all directions, but when it happens within the energy barrel, the energy is channeled and directed towards the end of the barrel at the unfortunate target.

This mode is fully automatic, and posseses a very high rate of fire, capable of discharging the whole plug in seconds. The lack of bullet casings to eject and the simplicity of design makes this a very reliable fire mode. Each loaded plug carries energy for thirty energy pulses.

• Orb launch - this fire mode utilizes specially designed charges, containing inert Combine energy orbs. The charge is placed on the tray underneath the energy barrel, with it's detonator against the firing pin. When detonated, the forward part of the charge disperses into six parts (thanks to it's construction and the fins), releasing forwards an energy orb.

Similiar to the primary fire mode, the mechanism required for this is very simple and reliable. Each charge carries a single energy orb.

Heavy machinegun variant

A heavy pulse gun in position

The OSI Pulse Rifle has also been modified by the Combine for use in entrenched positions, as a heavy machinegun, to provide firepower in a compact and easy transportable package.

This version of the pulse rifle differs from the standard version drastically. The orb launcher is removed, and the rate of fire amplified, to allow continuous suppressing fire. The barrel was redesigned and lenghtened to accomodate the weapons increased rate of fire and avoid overheating. The barrel, instead of being enveloped in a metal case, now consists of only the red resistant material that was a component of the OSI's barrel. Three armour plates are attached to it for protection, outfitted with a searchlight, allowing it's use in all lighting conditions. Also, the ammunition feed was redesigned to provide the appropriate amounts of ammunition for the weapon.

The gun is used in conjunction with an articulated weapon mount which is required in order for it to be used effectively, as it isn't intended for infantry. The weapon mount is articulated and allows firing in nearly every direction in the frontal 180 degrees. Two clamps allow for the mount to be attached to any solid surface, including railings. And since the weapon was designed as a mounted heavy machinegun, the stock and pistol grip were removed, replaced instead with two handles, more suited for emplacements.

Employment

The Overwatch Standard Issue, as it's name suggests, is primarily employed by the Transhuman Arm of the Combine Overwatch. It's versatility, accuracy and reliability make it an excellent choice for troopers operating often in hazardous conditions. It is also the exclusive weapon of the Combine Elite, who operate it with even deadlier skill than regular troopers. Additonally, only the Combine Elite are authorized for energy orb charges, since their employment requires high precision and proper training.

The heavy machinegun variant is used in entrenched positions and bunkers, as it provides extreme firepower in a very mobile and compact package. It's use is authorized for all branches of the Combine military, from Civil Protection to Combine Elite.

Tactical Considerations

The OSIPR is an exceptionally powerful weapon if used correctly, but like every weapon in Half-Life 2, it has distinct advantages and disadvantages.

The easiest way to use it is simply as a more powerful version of the SMG, which makes a great deal of sense, as the two weapons are seem greatly similar at first. However, the OSIPR has a number of major differences from the MP7 that more experienced players should take into consideration.

• First, one must resist the urge to unload the weapon all at once, because it can only hold two spare clips of ammunition, which, combined with its high firing rate, cause it to tear through its ammunition like it tears through enemies. Fire in short bursts to conserve ammo.

• Next one should note that it is highly accurate when fired in short bursts. Again, this also conserves ammo.

• The cores that power the weapon's alternate fire are rather hard to come by. Conserve them, and when you have to use them, try to line up your enemies so that it goes through them all before it hits a wall, because having the ball to ricochet off a wall requires a bit of guesswork.

• Note who you're using the weapon against. Try to avoid using the OSIPR against antlions or zombies, because they do not carry ammunition for it, and it cannot carry a lot of ammo to begin with. Try using it against Combine, as they are likely to have at least one OSIPR user in their squad after you've acquired it.

• The OSIPR also has a seldom-used defensive function. If it is equipped when a grenade lands nearby, the rifle can be used push the grenade away by shooting it repeatedly until it is a safe distance from the player. This tactic provides an alternative to the more dangerous expedient of using the gravity gun to throw the grenade back at the attackers.