Weapons in the Re-imagined Series
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A kinetic energy weapon is a weapon that causes damage as a result of the kinetic energy (motion) imparted to a projectile. This includes firearms firing solid bullets first and foremost but may also include guns firing explosive shells.
In fan circles, the battlestar and Viper weapons are sometimes called railguns. However this has never been stated on screen and a lot of evidence, like the use of chemically propelled rounds, points to them being conventional guns. Indeed, the exact nature of these weapons is still being discussed by the production team (some like Gary Hutzel want them to be based on railgun technology, while some in the writing staff feel that they are not railguns) .
Colonial battlestar armament
Colonial battlestars are armed with large gun turrets, but their layout varies from class to class. On Galactica type battlestars they are mounted on the dorsal surface, whereas Mercury class battlestars have forward-firing bow batteries, as well as smaller batteries along the sides of the flight pods.
These are the main offensive weapon of a battlestar, but are also used to lay down defensive fire against incoming enemy ordnance and fighters.
Point defense guns
Galactica type battlestars are equipped with numerous point defense guns located along the entire sides of the flight pods in twin mountings . The entire system is tasked with destroying incoming projectiles. Sensors and expert systems identify and evaluate threats, assigning priorities to them based on data like distance and projected trajectory, while at the same time laying the cannon; this and firing are all done too quickly for a human crew to match.
Although the main batteries are also used to engage incoming fighters and missiles, the point defense guns have a much higher rate of fire, thus making them more effective in that role. Both the point defense and main guns can work in tandem during combat to create a flak field around a battlestar in addition to targeting incoming enemy munitions over significant distance. Flak walls are generally cast less than half a dozen kilometers away from the ship, with a possibility to dial the delay of a flak projectile's time fuse. Automatic IFF targeting systems, pre-planned firing solutions and corridors presumably allow Vipers to safely launch through such a bombardment (He That Believeth In Me).
Some battlestars, such as Valkyrie carry conventional missiles (Hero). It is unknown whether Galactica or Pegasus share this ability, although it is likely that the missile tubes could also be armed with non-nuclear weapons. Unlike the Cylons however, Colonial battlestars use their gun turrets as main weapon.
At least one ship in the civilian fugitive Fleet, the Adriatic, has been armed with short range ship-to-ship missiles (Home, Part I). However, it is lost when traversing a dense star cluster (The Passage).
Battlestars carry a number of nuclear warheads. The standard number for a fully equipped battlestar is unknown, but Galactica still had five warheads at the time of its decommissioning, and was resupplied by Pegasus with at least four more (after using two).
Cylon basestar armament
Whereas the Colonials prefer artillery-style guns, the Cylons favor chemically-propelled missiles. Most of these missiles are fired from launchers located within the "arms" of a basestar. Like Colonial weaponry, the Cylon missiles can carry both conventional and nuclear warheads.
Basestars appear to have no point defense weaponry. Rather, they seem to rely their large Raider squadrons to provide protection from enemy batteries.
During the attack on the Twelve Colonies, the Cylons choose to undermine the Colonial Fleet's defense network by corrupting the Colonial Command Navigation Program. It is unknown how the Cylons would have fared in a direct confrontation with Colonial forces, but it appears that several battlestars working together would overcome the defensive capabilities of an equal number of basestars in a protracted battle. An example of this is the two-on-two battle in "Resurrection Ship, Part II", where a pair of basestars devoid of Raiders are quite effortlessly taken down by two battlestars. Additionally, Admiral Adama later feels confident that Galactica, even at half-strength, can hold off a pair of basestars while the colonists escape New Caprica (Exodus, Part II).
Small craft armament
Viper and Cylon Raider
These are most likely autocannon systems, with at least some models utilizing belt-fed ammunition (Kobol's Last Gleaming, Part I). The show's KEW are similar those found in real life in that they use chemical propellant to fire relatively small caliber projectiles from a single barrel at a high rate. The shells themselves can be solid, relying on their high velocities to impact and "shred" the target vehicle or fused to explode on impact. However, Viper ammunition shown on screen are also large enough to be explosive-filled and fused. A mix between armor-piercing slugs and explosive ammunition is also possible . The size of the Mark VII's guns and the profile of the rounds in motion suggest a smaller caliber than those of the Mark II, although the two have been described to share the same ammunition (Epiphanies); the two guns also appear to differ in their rate of fire.
Viper guns appear to be aimed entirely by the pilot during combat without the aid of any heads-up information being displayed. However, for such a weapon to be effective, the guns themselves would be harmonized (aligned for accuracy of and desired rate of fire) and the aiming system given a suitable period of deflection (the effective ability to follow, or "lead" a target into its line of fire).
The Cylon Raiders carry at least two KEWs of similar caliber to those of the Mk II Vipers. However, there are also two smaller barrels visible on their underside, making for two barrels of different sizes per side. It is possible that these are smaller caliber KEWs. Whereas the larger caliber KEW could be firing explosive rounds, smaller caliber KEWs could be firing slugs. The scene in which Kara Thrace loads the captured Cylon Raider in "Kobol's Last Gleaming, Part I" would seem to support the four gunned Raider hypothesis, as the rounds she is loading are too small for the larger, more prominent barrels' bores, but about right for the smaller barrels. Furthermore, in "Epiphanies", Viper ammunition is shown to be a typical autocannon round in the 30mm neighborhood, and a much closer match for the Raiders' larger barrels (although they look a little large for the Vipers' gun barrels).
While Vipers usually rely on their cannons, they can be equipped with missiles - conventional and nuclear - when needed.
Shortly after the attack on the Twelve Colonies, a Raider fires three nuclear missiles from internal bays at Galactica (Miniseries).
Vipers can be seen using missiles during the Battle for the Tylium Asteroid (The Hand of God), in a training exercise (Home, Part I), and during the Battle of New Caprica, where they are used to destroy Centurion guard towers (Exodus, Part II) and during Gaeta's Mutiny in an attempt to take down President Roslin's Raptor. (Blood on the Scales)
During the Battle of the Resurrection Hub, several Vipers are armed with nuclear missiles (presumably supplied by the Cylons) and use all of them to destroy the Resurrection Hub and two guarding basestars at the conclusion of the battle. (The Hub)
The Colonials use a wide variety of pistols, rifles, and machine guns. Most of these are identical to real-world weapons. For a detailed comparison see: Small arms
The only named sidearm in the series is the Stallion pistol, which is not military issue, however (Home, Part II). Admiral Cain has a large collection of older hand weapons in her office (Pegasus). The most distinctive Colonial weapon is the Colonial Fleet standard issue pistol, which comes in two variations. It is a small bore semi-automatic pistol, with a bigger launcher attached under the barrel. This muzzle-loaded launcher can fire a single high-explosive round with each reload. It is carried by both Viper and Raptor pilots on all missions. The design was in use as early as the First Cylon War (Razor Flashbacks, Episode 4).
The ammunition's effectiveness is dependent on the armor of the target. While stranded on Caprica, rounds from Helo's pistol go straight through the head of a Centurion ("33", "You Can't Go Home Again"). However, Centurions boarding Galactica are equipped with better armor and the standard rounds prove to be completely ineffective against the boarding team. Explosive rounds are used by the defenders, which destroy Centurions' heads with a visible explosion. Since Galactica is not stocked with large amounts of this type of ammunition, it is not standard issue and only used when really necessary (Valley of Darkness).
On Kobol, the larger explosive rounds launched from a grenade launcher destroy a Centurion in a single shot with a large explosion, while standard pistol rounds are sufficient to disable Centurions (Home, Part I).
During the Battle of New Caprica, the resistance fighters use their weapons to disable Centurions from an unspecified range, indicating that either armor piercing rounds are being used, or the Centurions have weaker armor than the aforementioned Centurion boarding party (Exodus, Part I and Part II).
In the Battle of the Algae Planet, Colonial small arms and ammunition are again proven to be ineffective, with the explosive rounds being the exception. However, only one explosive round is ever fired during the short ground battle between Colonial and Cylon forces before the Colonials withdraw (Rapture).
Cylon Centurions have a gun integrated into each of their arms, which serve as their main weapon. These guns fire armor piercing rounds of an unspecified caliber at high rates of fire, creating effective suppression fire against oncoming targets ("Valley of Darkness", "Exodus, Part II"). Centurions are also capable of sniping enemy targets from long distances (Rapture). It is unknown whether the arm guns or an unseen sniper rifle are used. However, some Centurions boarding Pegasus during the Cylon attack on the Twelve Colonies carry large machine guns in their hands (Razor).
Centurions during the First Cylon War carried a large caliber submachine gun type weapon. The weapon may have been a human weapon issued to the Cylons before their revolt, since William Adama easily made off with the gun he obtained from a fallen Centurion (Razor Flashback, Episode 4).
Plastic explosives like G-4 are used by humans in several forms, ranging from small quantities for forcing open doors to larger packs for heavy demolition work.