Imperial Ordnance

Infantry win firefights, tanks win battles, artillery wins wars.

That's how the saying goes. And it's true. Without the big guns you are doomed to be murdered gruesomely for the lulz of it, get eaten or have your soul used as a condom for all eternity. The Imperium knows this and has devised a truly staggering amount of heavy guns dedicated to ruining your shit into next Sunday from anywhere in between half a mile to half a continent away.

Man-portable Weapons

The lightest of indirect support weapons can be carried by individual or paired soldiers. While this makes them tactically more flexible, they have reduced firepower compared to their heavier counterparts.

Grenade Launcher

Grenade Launcher

The grenade launcher is a light, man-portable weapon capable of firing small explosive charges. It is primarily employed by the Imperial Guard, with almost every trooper squad featuring at least one of them. Grenade launchers are a common weapon used by Imperial Guard infantry squads thanks to their ability to lob grenades greater distances and with more accuracy than can be thrown.

Their primary duty is to lay down suppressive fire and destroy light vehicles and buildings. It has a choice of two different payloads, anti infantry Fragmentation grenades, and anti-armour Krak grenades.

Space Marines scout bikers utilise a variation of this weapon, the "Astartes pattern" Grenade Launcher. It fires the same rounds, but with an increased rate of fire.

Vengeance Grenade Launcher

Vengeance Grenade Launcher

A grenade launcher only found in the Vidya Game of SPEEES MEHREEEEENS!

A much more tactical weapon than its assault-orientated cousins.

The Vengeance Grenade Launcher is an experimental Adeptus Mechanicus weapon created on the Forge world Graia just prior to the Ork invasion of Warboss Grimskull. The Vengeance Grenade Launcher is not authorized for use off world, but those Space Marines who have field tested the weapon attest to its effectiveness against a range of targets. The launcher can fire out up to five fusion charges that stick to surfaces and then be remotely detonated.

The current status of this weapon is unknown.

Grenadier Gauntlet

Grenadier Gauntlet

Think of it as a heavy grenade launcher or a sawn-off Missile Launcher.

The Grenadier Gauntlet is a type of heavy Grenade Launcher used by Imperial Guard Bullgryn. Like all Ogryn weapons such as the Ripper Gun, the Grenadier Gauntlet is not meant for accuracy and range, instead it is constructed like a giant baton. The grenade launching mechanism is just a feature for the Bullgryn to launch something explosive at an enemy he can't reach.

The foes are often left reeling and shell-shocked even before the maul-wielding Ogryns charge into their midst and bludgeon the survivors into a red paste.

In terms of the firing mechanism, the Grenadier Gauntlet obviously works like any normal grenade launcher. However it does have a lower set of ammunition due to the Ogryn's natural stupidity and inability to understand the concept of reloading.

Still, as a baton, it is naturally incredibly tough to withstand the immense strength of a rampaging Ogryn as well as simple enough to use for these dumbasses.

Grenade Harness

Grenade Harness

The Cyclone Missile Launcher of Grenade Launchers.

The Grenade Harness is a type of Grenade Launcher mounted on some Space Marine Terminator Armour. These launchers allow for a barrage of Frag grenades, usually before a charge by the Terminators.

The Grenade Harness has a lower ammunition capacity than a regular Grenade Launcher due to its smaller size. It is thus used tactically in surgical strikes in order to maximize the weapon's potential.

Like the Cyclone, it functions the same way but with an obvious decrease in weapon range and output.

Balistus Grenade Launcher

Balistus Grenade Launcher

A new type of grenade launcher wielded by the Golden Boys in Shining Armor.

Balistus Grenade Launchers are potent ranged weapons wielded by the Adeptus Custodes, which excel at piercing armor like a giant Bolter. The only users of these weapons are the venerable Allarus Custodians. It is unknown if the more common Aquilon Terminators (assuming they still exist) have permission to carry these around.

Like the wrist-mounted bolters carried around by Gray Knight Terminators, the Balistus Grenade Launcher works on the same principle. Except, instead of providing covering/suppressing fire in close to medium range, these things mulch infantry at longer ranges.

It is unknown where the Grenade Launcher stores its ammunition, given the relative size of the barrel in contrast to the size of the weapon itself. Maybe it is a single shot weapon?

Heavy Grenade Launchers

A much bigger variant of the standard grenade launcher that peppers the battlefield with explosive munitions.

Auto-Launcher

Auto-Launcher

Resembling a rack/box of grenades.

Auto-launchers are vehicle-mounted grenade launchers similar to smoke launchers. They are simple, six-barreled weapons mounted on vehicle hulls, firing salvos of all three grenades types at a time.

They are used on Imperial vehicles. Loaded with frag, krak, or blind grenades, they are useful for close defense and laying smoke screens. The auto-launcher carries six grenades, all of the same type.

The Auto-Launchers are best identified by the literal racks of exposed grenade/missiles pointed randomly everywhere. Why the Imperium thought it was a good idea to place these weapons on extremely random places is unknown since these grenades would not be able to hit its targets tactically...unless those grenade could home on its targets of course. Alternative, they are designed to lay down smoke screens, so having them cover all angles is a good thing.

The Repulsor is the most infamous user of these weapons.

Fragstorm Grenade Launcher

Fragstorm Grenade Launcher

Think the Grenade Harness for Dreadnoughts.

Fragstorm Grenade Launchers are a type of grenade launcher used by Primaris Space Marines. Like the Grenade Harness, these launchers allow for the firing of a barrage of frag grenades before a charge. However, they can also be used defensively when the Dreadnought is surrounded by enemies and they just need to pepper a targeted radius with shrapnel and explosions.

They are equipped for anti-personnel roles to Aggressor Squads and Redemptor Dreadnoughts.

Their more tank-busting equivalents is the similarly named Krakstorm Grenade Launcher.

And no, despite their appearance, they have in no way related to the Auto-Launcher by function.

Krakstorm Grenade Launcher

Krakstorm Grenade Launcher

It's literally a Fragstorm Grenade Launcher that fires, you guessed it, Krak Grenades.

A Krakstorm Grenade Launcher is a type of Imperial Grenade Launcher usually wielded by the Primaris Space Marines that fires a volley of three aforementioned Krak Grenades at a time upon the enemy. It is deployed for use as an anti-armor or anti-fortification weapon by Repulsor grav tanks.

Although there is no evidence of it being mounted on the Redemptor Dreadnought, the fact that the ammunition of both the Frag and Krak are superficially similiar means it wouldn't be that out of the blue if GW decides to update the Dreadnought with these weapons.

Like the Auto-Launchers, the Krakstorm Grenade Launcher carries the same issue of it being awkward to aim, with the only logical explanation if that the Krak grenades themselves have homing features like that of a missile.

In terms of rules, they act as they are named. Good vehicle killers, although the sheer amount of anti-tank weapons that the Repulsor carries means that these weapons are best used for killing any stragglers.

Mortar

A mortar is an artillery weapon that launches shells in a high arc. They tend to have relatively short barrels and fire shells at relatively low velocities. The Imperial Guard uses them in two sizes: the standard man-portable mortar, carried and operated by two Imperial Guard troopers; and the heavy mortar, which can be used in static or towed artillery mounts, or mounted in a Griffon Heavy Mortar Carrier. They can destroy light infantry and light vehicles easily enough, but are unlikely to trouble heavy infantry or vehicles with tank-grade armour.

Light Mortar

File:Mortar2.png

Light Mortar

The most common form of Mortars is...well....the Mortar. Some may call it the Light Mortar due to the smaller payload and size but whatever. The Mortar looks like...a basic modern Mortar found in use in today's armies. I guess the design haven't change for over 40,000 years, but hey, if it's not broken, don't fix it.

The Light Mortar fires an explosive shell on a high-arching trajectory capable of flying over the heads of nearby troops and crashing down on the rear ranks of the enemy. Its primary use is in the anti-personnel role, breaking up enemy infantry formations and pinning them down.

Mortars are prized for their ability to lay down a curtain of fire from behind cover, and while not particularly accurate their explosive power makes up for this deficiency. However this indirect-fire capability requires accurate targeting information to be effective and the use of spotters with proper vox-protocols in order to avoid friendly fire. Standard procedures has the spotters locate targets, whether through visual or remote-servitor means, and send a fire request to the mortar crew's Platoon Command Squad, which plots a firing solution and relays that information to the mortar teams assembled, adjusting fire as required.

Mole Mortar

Mole Mortar

Basically a reverse Mortar. In that it travels underground rather than overhead. It's more of a torpedo then a Mortar, but it got 'Mortar' in the name and we need to stick it somewhere.

The missile burrows its way toward its target, bypassing all surface hazards and defenses, emerging from the ground beneath the target. The missile is self-guided and able to track its target through solid rock. As an invention of the Sphess Dorfs, the Mole Mortar soon found its way up the ranks of the Imperial Guard due to its unorthodox firing methods.

The Mole Mortar was originally developed to destroy enemy tunneling vehicles but was so successful that now used as a short-ranged assault weapon, even though such premonitions sounds outright Stupid let alone suicidal, it is worth remembering that since vehicles have thinner bottom armor if you can get a hit on a tank it's going to be fairly devastating. It is sometimes used to breach fortifications too strong for conventional weaponry to damage. Due to the unique way it operates, the mole mortar is able to circumvent most defenses, striking from below to explode within bunkers and other structures.

Heck, the Mole Mortar was so popular in the Guard that it eventually led to the creation of the Mole Launcher. Figures.

Heavy Mortar

Heavy Mortar

The Heavy Mortar is a larger support version of the standard Mortar used by the Imperial Guard. Its primary advantages are a wide range of ammunition types, a high rate of fire, and simplicity to construct and maintain. However its massive size means the heavy mortar must either be towed into place by a Trojan or Centaur. A special version of this is mounted on the Griffon Mortar Carrier.

While they were once quite popular with many Imperial Guard regiments, the use of heavy mortars has fallen out of favor in recent years, since for many commanders it lacks both the heavy firepower and long reach of much larger artillery pieces, limiting its use in box-barrages or counter-battery fire. Towed heavy mortars have become even less popular, being seen as too slow to keep up with advancing mechanized units, and have largely been regulated to PDFs and Siege Regiments.

For all their faults heavy mortars also have a number of advantages. They are an excellent close support weapons for engaging enemy infantry and light vehicles, freeing the heavier artillery for use against more appropriate targets, and can maintain a steady rate of fire for hours. Its versatility also allows it to fulfill a variety of other roles, from launching illumination shells during night battles or laying down a smoke screen before an infantry attack.

Karacnos Mortar Battery

Karacnos Mortar Battery

The Adeptus Mechanicus have their own mortar and it is a mortar to rule them all. Called the Karacnos Mortar Battery which is so named after the vehicle it is mounted on. The Karacnos Mortar Battery is special cause it uses radioactive warheads as its armaments! You can't get more metal than that! As it is basically firing a barrage of dirty bombs, this mortar fires its radioactive warheads which is designed to sweep an area clear of all organic life.

As you can imagine, these badboys aren't that well liked for those Imperial Commanders who want to have a idyllic and livable planet to prosper. Seriously, a couple of these batteries would turn a city into a uninhabitable wasteland that only a Krieger from a Death Korps would enjoy.

On tabletop (The 30k rules at least), the Mortar is a R60 heavy bolter with barrage, small blast, fleshbane, radphage, Ignores cover and pinning which seems good on paper but with the majority of targets getting armour saves this mostly equates to a longer range Wyvern.

Tank Guns

These guns are too large to be carried by infantry (excluding "heavy" weapons such as lascannons and autocannons), but are still small enough that a heavy vehicle, like the Leman Russ Battle Tank, can carry and fire them while in the thick of battle. It should be noted that certain Autoweapons are also a form of ordnance. So don't be too surprised if you see a few similiar faces around here.

Battle Cannon

Battle Cannon

The primary weapon of the Leman Russ Battle Tank, it is the most commonly used tank gun for good reason: the Battle Cannon can pull double duty as both an anti-tank and anti-infantry weapon thanks to its considerable range (72"), strength (S8 AP3 = instant death to MEQs and capable of damaging any vehicle) and explosion size (5" blast = blob-killer). The cannon proved so popular that it was made the primary armament of the Macharius and Malcador super-heavy tanks, and has been forked into several versions by the Adeptus Mechanicus:

Battle Cannon (Leman Russ)

Range	Type	S	AP	Special Rules
72	Ordnance	8	3	Blast (5")

Since the revamping of the AP-system and moving away from "blast template" mechanics, the stats for battle cannons were changed, becoming something of this

Battle Cannon (8th Edition)

Range	Type	S	AP	D	Abilities
72	Heavy D6	8	-2	D3	-

It is worth noting that while AP-2 now allowes 3+ and 4+ armour to actually provide at least some save-roll (5+ save for 3+ armour and 6+ save for 4+ armour), 2+ armour (like that of the Terminators) now only get 4+ save instead of 2+.

Conqueror Battle Cannon

Conqueror Battle Cannon

Fitted to the Leman Russ Conqueror, this is essentially a lighter and smaller version of the Battle Cannon. Its shorter range and smaller blast radius is more than compensated by the reduced recoil and higher rate of fire, allowing for an even greater damage output than a Battle Cannon. Like the battle cannon the Conqueror cannon is capable of firing high explosive, anti-tank, smoke, illumination, and even Hunter shells, although not infernus rounds. The Forge World Gryphonne IV also designed a special shell just for this weapon, known as the Augur Shell. While similar to an HE shell when the Augur's impact detonator is triggered the thin shell wall splits open and the soft explosive charge is spread across the target; a microsecond later the secondary detonator in the base of the shell ignites the explosive. This causes cratering and cracking of the target's outer armor, while inside the target it produces spalling capable of damaging internal equipment and wounding or killing personnel (Which sounds extraordinarily similar to HESH ammunition). However the shell was not considered a success and in the end relatively few were produced.

On the tabletop, it's a "Heavy" weapon, as opposed to "Ordnance", which allows the carrying vehicle to fire its sponson weapons at full ballistic skill (though, since the Conqueror is not a heavy tank, that only applies if it holds still...).

In 8th Edition it's just a Battle Cannon with 50% of the range (36").

Macharius Battle Cannon

Macharius Battle Cannon

The Macharius Heavy Tank has a twin-barreled variant of the Battle Cannon, because it has a bigger turret and because two barrels are better than one. It also looks like it has a larger bore which means it can fire larger calibers. For all intents and purposes, the Macharius Battle Cannon should be considered as a superheavy weapon if not for the fact that the Macharius itself is not completely in the superheavy category.

It used to actually fire two shots, but that's been changed to a single massive (7") blast in more recent publications similiar to how some video games give sawed-off shotguns a firing mechanism to blows off the two barrels at the same time. Maybe they will get around to making a single massive cannon for it, too. A Macharius Vanquisher Cannon? It exists. But a Macharius with a giant single gun? we wish.

Then 8th Edition drop and we went back to a 2-shot Battle Cannon. Lame.

Vanquisher Battle Cannon

Vanquisher Battle Cannon

Huge gun, huge range, huge barrel, huge damage. Basically an anti-tank gun fitted on tank destroyers. The Leman Russ Vanquisher has its weapon tooled for only one purpose: to fuck enemy tanks and monsters hard using huge shells.

It sacrifices its blast radius for an improved capacity for armor penetration (AP2, S8 + 2d6 = 10-20 with an average of 15 = roll for the circumference of the hole that is about to get punched through your armor). The Macharius can carry twin-linked Vanquisher cannons, and has enough internal space that it can also fire high-explosive shells like the regular Macharius Battle Cannon, so it's like two tanks in one -- and it costs about as much as regular Russ and a Vanquisher put together.
Worth noting, that the cannon is now somewhat nerfed, being given only S=8,AP-3 while retaining Heavy 1 and gaining D=D6R (the same rule as meltagun, albeit not only when in half-range or less).

The only problem is that the Adeptus Mechanicus lost Tigrus, the only Forge World that made Vanquisher cannons, to the Orks in M35 (somehow, you'd think the Imperium would throw so much firepower in defense of such a vital world that nothing could take it), so the only way to make new Vanquisher tanks is to take the cannons off of tanks that have been immobilized -- not a simple feat, given that the cannon is so dangerous to armor and stands out as a priority target for enemies. Two other Forge Worlds, Stygies VIII and Gryphonne IV have stepped up to try and match the old cannons (read: Forge World, the company, has produced two alternate turrets for Leman Russ Vanquishers), but they're just not quite there (though it makes no difference on the tabletop, of course). And then Tyranids ate Gryphonne. (It was delicious.)

And it also seems, that as per 6-th edition Astra Militarum Codex and onwards, the fluff was changed to do away with "Vanquisher cannon being rare" altogether - now the Leman Russ Vanquisher is noted as being simply the dedicated anti-armour variant of Leman Russ, often employed as command tank in armoured formations. However, it now also seem that Vanquisher cannon now lost it's ability to fire HE rounds, being able to only fire anti-armour HEAT rounds, something ineffective against infantry formations.

It should be noted that, unlike how many on /tg/ perceive it, the Vanquisher is not just a Battle Cannon firing specialised Anti-Tank shells. The Guard does use separate specialised HEAT shells for the basic BC, but Imperial Armour shows the Vanquisher Cannon to have a smaller bore than the standard one, while the shells have a greater diameter-to-length ratio and possibly be some form of APFSDS round.

Demolisher Cannon

Demolisher Cannon

The Big One. Fitted onto the Leman Russ Demolisher and packing enough heat to turn Terminators and heavy and super-heavy vehicles inside-out with a single shell, the Demolisher Cannon's short range (24" -- shorter than some infantry weapons) is the only thing that stops it from being a truly amazing weapon.

Even then, it can cause considerable damage (S10 AP2 Large Blast = kiss your everything goodbye) and because it is smaller than the other cannons, is one of the few ordnance weapons used by the Space Marines, mounted on the Vindicator and Land Raider Ares, and it is used as secondary armament on certain super-heavy tanks, like Baneblades and the Malcador.

The Demolisher fires special ammunition much larger than that used in the Battle Cannon, allowing it to punch through layers of concrete and plasteel alike. A Demolisher shell is constructed with an outer layer of standard high explosive and shrapnel, which surrounds a chemical core. Upon impact, the explosive layer detonates, punching a hole in the enemy's armor and spreading shrapnel over a wide area. It also starts a chemical reaction in the core, causing it to super-heat into a jet of plasma, which lances through the compromised armor, spreading molten death over a wide area and literally ripping the target from the inside out. The tremendous recoil produced by firing the cannon is capable of lifting the front end of a tank off the ground and, were it fired while moving, risk causing it to roll over.

Eradicator Nova Cannon

Eradicator Nova Cannon

The Eradicator Nova Cannon fires shells with an unstable "sub-atomic" core (yes, this just might be a tank cannon that fires mini-nukes). These shells are somewhat hazardous to the tank and crew, as they have a non-zero probability of exploding if they get jostled while loading, so most regiments that use Leman Russ Eradicators have a margin for crew losses, and that is without the off chance of radioactive leaks from a faulty shell.

The Eradicator is most effective supporting infantry forces fighting in areas such as cities and jungles, and it is easily replicated on dozens of Forge Worlds. For urban combat however the Eradicator does not feature the additional rear armor found on similar vehicles, leaving it vulnerable to attacks from behind.

They keep using the Nova cannon, though, because the shell's massive blast completely flattens any cover, so unless the targets are power armored, there's no escape for them (S6 AP4 = Instant Death for most standard infantry; less effective for beefier troops). Why a shell that detonates if it's shaken does not go off when it's fired from a freaking cannon is not completely explained by GW.

Super-Heavy Tank Guns

Technically, these guns can be carried and fired by a vehicle in direct combat, but because that vehicle has to be the size of a Baneblade, they deserve a category of their own.

Accelerator Cannon

Accelerator Cannon

The main gun of the Fellblade. It fired armor-piercing explosive self-guided "darts" via either magnetic acceleration or gravity impellers. It was also twin-linked, though the Fellblade had severely limited ammunition for it, relying mostly on its other weapons until a suitable target presented itself.

This type of cannon used a complex overpressure mechanisms of a special vacuum-based system which can propel heavy shells with greater force than a conventional cannon of similar size. This system is so efficient that they provide very little recoil from every shot, making the Accelerator cannon extremely stable and accurate. The loading mechanism of Accelerator cannon is also highly advanced and served by a special loading mechanism that allows the tank’s commander to switch ammunition type at a little notice.

It was made on the Forge World of Tigrus (home of the original Vanquisher cannon -- which resembles the Accelerator Cannon quite closely, with the long barrel and large muzzle brake). It can fire high-explosive shells comparable to a super-charged Battle Cannon (S8 AP3 7" Blast) or armor-piercing shells comparable to what would later become the Vanquisher battle cannon (S9 AP2 3" Blast, rolling 2d6 for armor penetration).

Its smaller brother is the Accelerator Autocannon.

Macro-Accelerator Cannon

Macro-Accelerator Cannon

Think of the Accelerator Autocannon on steroids. The Macro-Accelerator Cannon is to the Accelerator Cannon in the same way the Accelerator Cannon is to the Accelerator Autocannon (Try and speak that sentence five times in a row).

The Macro-Accelerator Cannon is a large kinetic weapon used by the Primaris Space Marines' Astraeus Super-Heavy Grav Tank as its primary armament. The Macro-Accelerator Cannon is actually a complex mass driver that uses a potent electromagentic field to accelerate a barrage of high caliber ferro-carbide slugs to extremely high speeds. It is basically an upscaled Imperial railgun. Usually twin-linked, these weapons unleash an onslaught against which even enemy heavy armor cannot stand.

Crunchwise, the fluff seem to match the rules. The Macro-Accelerator Cannon is a vicious Heavy 12, S8, AP-2, Damage 3 that ignores all abilities that impose negative hit modifiers when targeting anything with the FLY keyword. Normal vehicles wouldn't even survive a barrage of these and superheavies would take a beating.

Baneblade Cannon

Baneblade Cannon

The Baneblade's primary cannon is an upscaled Battle Cannon, improved in strength, armor penetration, and blast radius (S9 AP2 10" blast = 10" wide lascannon pie-plate). Its special shells are not propelled by an explosion, but are rather miniature rockets that increases the shell's range and accuracy tremendously. However, this also leads to the danger of a build-up of gasses in the barrel, which can cause serious harm. To combat this the Baneblade Cannon is built with a double-sleeve design with venting ports studded around the cannon's muzzle, allowing these gasses to escape under their own pressure.

When fired the shell leaves the barrel under its own blast pressure with speed maintained whilst the rocket burns, with each booster burning out and falling away as the next one ignites. This means that the Baneblade's Cannon works on a similiar basis to a upscaled Bolter -- a feature that "counterfeit" Baneblades produced on other Forge Worlds are unable to reproduce, and so they substitute standard battle cannon rounds for them. There's no indication that they're much, if at all, different, though.

Dreadhammer Cannon

Dreadhammer Cannon

Back in the Great Crusade, Perturabo asked the Adeptus Mechanicus to build him a new cannon that could level buildings with a single shell and be carried at a reasonable speed. Because the Horus Heresy hadn't happened yet, and they were thus still feeling like innovating now and then, the tech-priests agreed, and built him the Dreadhammer.

It fires shells that weigh several tons, and experiences so much recoil that even the super-heavy Typhon Heavy Siege Tank has to limit the propellant used (and thus the range) if it wants to fire on the move. At first, people made fun of Perturabo for asking for (and getting) a super-Demolisher, but it has a bigger blast radius and, if the Typhon stays still, a longer range, and it really does shake buildings to their foundations. The appearance, name, and firepower of the Dreadhammer cannon suggest some connection with the Baneblade-mounted Hellhammer cannon.

Hellhammer Cannon

Hellhammer Cannon

The comically small Hellhammer Cannon is the main weapon of the Hellhammer tank. Resembling a Baneblade with micropenis issues, this gun has spawned numerous compensation jokes at the tank's expense. Still, every nerd has its day and one thing the Hellhammer excels at is in its ability to fire mini-nukes.

The Hellhammer Cannon fires shells with a building-busting sub-atomic charge (like the Eradicator Nova Cannon). Each shell weighs 180 kilograms and is propelled by a rocket motor, with exhaust vents on either side of the barrel allowing for the safe discharge of gas with every firing. Due to the sheer weight of the shells, an automatic loading tray assists the loader, limiting the weapon's rate of fire. The tremendous concussive explosion (S10 AP1 7" Blast) is enough to collapse a building in one shot (Ignores Cover), so crews are trained to fire at the ground floors of structures that need to come down. The short barrel and recoil compensators give the cannon a very short range (a measly 36"). As such, the Hellhammer cannon is only used on tanks that are built for urban combat, like the Hellhammer super-heavy tank.

Quake Cannon

Quake Cannon

What has already been said about the Quake Cannon in the Autogun category has been said here. The Quake Cannon is an Awesome gun with a Stupid construction process. The quintessential fortress fucker supreme.

The Quake Cannon is an odd beast; its firepower is not unusual for a weapon of its size (S9 AP3 10" Blast), but it has a longer range than any other tank gun (180", only exceeded by the Earthshaker and Colossus cannons), and is normally an arm weapon for Warlord Battle Titans.

It is occasionally mounted on a Baneblade chassis to make the Banesword, essentially a super-heavy self-propelled artillery piece, primarily employed against fortifications. Also, it's ammunition is filled with the echoing shockwave of a world that was subjected to Exterminatus, and the sound it makes as it flies through the air is said to be the screams of those who died in the exterminatus that powered it.

Stormsword Siege Cannon

Stormsword Siege Cannon

The Stormsword Siege Cannon fires big bunker-busting rocket-propelled shells. Unfortunately, the Adeptus Mechanicus never considered that crews might want to fire at things other than ground floors of nearby buildings, so the cannon cannot elevate very far (though, if it did elevate too far, the recoil might just rip it out of the turret). It makes up for this by being able to turn entire city blocks to dust with a single shot.

The weapon and vehicle itself is built specifically for sieges and street-fighting, the Stormsword is geared towards providing troops close-quarter support with a variety of heavy weapons whilst its cannon is used to lay waste to entire encamped bunkers and buildings.

It used to be that the Stormsword just had a Hellhammer Cannon that couldn't swivel, but apparently that made them too similar, so in the sixth-edition version of Apocalypse, GW made the Hellhammer Cannon a 7" blast and left the Stormsword with the 10" pie-plate.

Tremor Cannon

Tremor Cannon

Most cannons launch shells that are fuzed to explode on or shortly before impact. Not the Banehammer's Tremor Cannon: after landing it buries into the ground before it detonates. This muffles the blast (S8 AP3 is actually the lowest-strength and worst AP of all the super-heavy tank guns), but it sends a tremendous shockwave through the earth that leaves enemies not caught in the blast stumbling and slowed. The fluff describes this as liquifying the surrounding terrain.

Imagine the ground under your feet giving way, suddenly having the consistency of water. By the time you've figured out what's happened, you're partially buried in the dirt and have to dig yourself out before the enemy comes and shoots you like a horse with a broken leg. And that's if you're lucky, it's entirely possible to get buried completely and suffocate to death under several feet of earth and rubble. You can see why it would be very, very bad to be on the receiving end of this weapon.

In theory it would also make a decent wall and bunker cracker.

Artillery

Sometimes, the Imperial Guard can't get in range to use tanks, or could, but only at a cost that even the Departmento Munitorum would find staggering, like when they are attacking enemy fortresses. To overcome such obstacles, the Adeptus Mechanicus had a brilliant idea: make even bigger guns with a longer range. These guns are so big that they cannot be fired on the move; they are often built into static defensive positions, or for regiments that need to be more mobile, they may have guns placed on towed platforms, or on self-propelled chassis (see Imperial Ordnance Pieces for more information).

Thunderfire Cannon

Thunderfire Cannon

Not to be confused with the SPESS DORF's Thunder-Fire Cannon. For the full page, see here.

Griffon Heavy Mortar

Griffon Heavy Mortar

The Griffon Heavy Mortar is the smallest and lightest of the artillery guns. This weapon has been a source of Skub in-universe.

Critics of the Griffon claim that its main weapon is too small to warrant its vehicular mounting, while tying up fire control and observation assets needed by much larger pieces. For its supporters though, the Griffon is the ideal compromise between weight, firepower, mobility and ease of use. Its heavy mortar is excellent against infantry and light vehicles, freeing heavier artillery for use against more appropriate targets, and can maintain a high rate of fire. The vehicle is also capable of keeping pace with rapid advances for which heavier vehicles like the Basilisk are too slow to maintain.

Its firepower is not impressive (it's S6 AP-1 and ignores cover), and its range is also relatively short (48"), but because it is so small and light, it can sustain higher rates of fire than other guns and, when carried in the heavy chassis of a Griffon Heavy Mortar Carrier, it can be fired indirectly and roll two dice dropping the lowest for number of attacks).

Stormshard Mortar

Stormshard Mortar

Take a mortar and give it the firepower of a machinegun. You get yourselves a Stormshard Mortar.

The Stormshard Mortar is an artillery system commonly mounted in two pairs on Imperial Guard Wyverns. These mortars excel in urban warfare, firing shrapnel down on enemy infantry without exposing the vehicle itself to harm. It is a fairly close range weapon for artillery, but it is needed in the heavily tight space of Hive Cities where the chance of an artillery shell hitting the rooftops of some poor hobo's house is actually quite high.

Because of the chance of facing against Horde Armies, the Wyvern mounts not one, but TWO sets of Stormshards. These means that these badboys carry four mortars on one turret. Add to the fact that they can fire on auto and you have a weapon system that eats Swarmers for breakfast. All of the fucking yes!

Given it's similarity to the Heavy Quad-Launcher, it is likely the same weapon firing different ammo.

Earthshaker Cannon

Earthshaker Cannon

The Earthshaker Cannon is the Battle Cannon of artillery pieces: common, highly recognizable and very lethal (S9 AP-3 Dd3 anywhere within twenty feet). It fires its shots further than any weapon except for the Manticore Launcher Tank and Deathstrike Missile Launcher.

This 132mm caliber weapon has a muzzle velocity of 814 meters per second and fires a 38 kg projectile, hitting targets over 15 km away in under 19 seconds, using the standard five powder charge.

Six and seven powder charges can be used to hit targets well beyond this range, however the additional wear and stress this causes on the barrel limits the number of overcharged rounds to twenty, with authorization for their use required. Only Earthshakers on static mounts can fire these charges, as vehicle mounts are considered too unstable for their use. The most common type of shell fired by Earthshakers are high explosive, but it can also launch incendiary, smoke, illumination, and even diamantine-tipped armor piercing shells. Shells fired by Earthshakers have been known to cause craters fifteen meters in diameter and obliterate infantry in an instant.

The Earthshaker is most often mounted on the Basilisk self-propelled artillery tank, though it also appears in static artillery positions as well as built into fortifications.

Amusingly enough despite being depicted as an artillery gun in 40k, the Earthshaker is modeled after the long-barelled WWII German Flak 88 rather than a field howitzer from the same epoch.

Medusa Siege Cannon

Medusa Siege Cannon

The Medusa Siege Gun is an aging siege weapon used by the Imperial Guard both as a towed artillery piece and mounted on the Medusa Siege Tank. Compared to the Earthshaker Cannon the Medusa fires a much larger shell at lower velocities. This gives it immense destructive capabilities, useful in breaching the walls of an enemy fortress or destroying bunkers in a single shot, but it consequently has a much shorter firing range, even compared to other siege weapons like the Bombard. For this reason they are less useful for harassing and counter-battery fire, but are still prized by many siege regiments for their ability to blast enemy walls, installations, bunkers and trenches.

The Medusa Siege Cannon is the shortest-ranged of the Imperium's artillery weapons at 36" (Breacher shells on the carriage to 48"), but it is not meant to launch munitions over fortified walls; rather, it is meant to shoot fortifications directly and destroy them (which it certainly does, at S10 AP-3 Dd3) -- and when regular shells aren't enough, they can fire special Breacher shells that sacrifice indirect fire for d6 damage to buildings.

Colossus Siege Mortar

Colossus Siege Mortar

The Colossus Siege Mortar is huge, cumbersome and highly destructive, and it's so large that its shells have to be loaded by cranes instead of by hand. It fires massive concussive rounds that will turn its target to paste (as long as it's a human wearing something less than terminator armor -- S6 AP-2 Dd3 is good against infantry blobs, not so much for harder targets), even if they are hiding in cover.

Because one cannon wasn't enough, the Imperium built the Dominus Armored Siege Bombard, a variant of the CRASSUS ARMORED ASSAULT TRANSPORT that carries an automated trio of Colossus cannons (though the Dominus only costs as much as two Colossi...which actually makes sense, as the Colossi are built on a Leman Russ chassis where-as the Dominus just has to pay for an extra cannon, not a whole new vehicle to carry it).

Dominus Triple Bombard

Dominus Triple Bombard

Hey! Remember how we said that a certain Imperium vehicle was actually big enough to mount not one, but THREE Colossus Siege Mortars? Well here it is, the Dominus Triple Bombard found only on the DOMINUS ARMOURED SIEGE BOMBARD. This monster is a god damned tarpit cleanser.

An automated battery of three Bombard cannons rigged to fire together in sequence, it can pulverize anything caught within its field of fire. The Triple Bombard has two rates of fire: a slower rate the Dominus is limited to when on the move, and the second a higher rate for sustained fire when it is stationary.

In practice the Dominus throws 10d6 S10 ap-3 shots with indirect fire when stationary, easily wiping any unit foolish enough to be larger than 5 models. S10 Ap3 is also a serious threat to any armor short of a titan, and the weight of shots pretty much guarantees an overkill of single model targets.

Basilisk Magnus

Basilisk Magnus

Get a Earthshaker Cannon. Pump it full of steroids and growth hormones and make it big enough to launch an Angry Marine at full force. Ladies and gentlemen, the Basilisk Magnus is born. Seriously, this thing is the size of a Baneblade.

Exclusive in Dawn of War or more specifically, the Soulstorm expansion. The Basilisk Magnus is a large artillery platform, defending the 252nd Conservator Regiment's stronghold in the Dussala Precinct on Kaurava I. It fires devastating rounds that creates a wide area of destruction, though it needs a spotter to acquire targets. If the artillery spotter is killed before the Basilisk Magnus' operators receive the targeting information, it will not be able to fire.

This honking piece of Rape was notorious for hitting something as small as a Gretchin from one end of the map. Shame there isn't a tabletop conversion....yet.

Thunder-Fire Cannon

Thunder-Fire Cannon

Not to be confused with the SPESS MEHREEN's Thunderfire Cannon. For the full page, see here.

Goliath Mega-Cannon

Goliath Mega-Cannon

A hilariously phallic weapon made by They-Who-Shall-Not-Be-Named. The Goliath Mega-Cannon, both the gun and the vehicle (Don't tell us why they decided to name both weapon and vehicle the same) is one of the largest artillery pieces ever known and fielded.

Basically each shell weighed several tons and was powerful enough to shatter entire fortifications and turn a fleet of Baneblades inside out. These motherfuckers were the Schwerer Gustav in all but name.

Curiously, the gun never really needed any shock absorbers to control the immense recoil. However it could be that the Goliath Mega-Cannon (The vehicle, not the gun) doesn't need one as the vehicle's own base is the gun's base.

The power of the Goliath means that each cannon fires its own barrage template. A Goliath attack is worth four barrage points plus the roll of a D6, giving a score between 5 and 10. The super heavy shells fired by the Goliath are so good at reducing fortifications to rubble that it ignores hit modifiers for cover altogether.

The Goliath lobs its shells high into the air to achieve its mammoth range, but it can't depress its barrel to hit a very close target. This means a Goliath can't shoot at targets closer than 50cm, so it has a min range of 50cm. They also don't have any self-defense secondary weapons so you need a few Thunder-Fire Cannons to offer cover support and picking off any units near the Goliath.

Of course, all of these rules are now outdated. But it is pretty cool to see the power it once had.

Behemoth Cannon

Behemoth Cannon

The largest artillery field piece to date. Until GW decides to one-up themselves and invent a even bigger artillery piece.

The Behemoth Cannon is a massive weapon that is the primary armament of the Capitol Imperialis. The giant landships that can be mistaken for a city block and is tall enough that a goddamned motherfucking Warlord Battle Titan can use for cover. The Behemoth Cannon is so large that four Leman Russ Battle Tanks could fit within its barrel (Although the models and artwork definitely disagrees with that statement), and the concussive force of firing the weapon can produce a mushroom cloud and shake the earth itself.

It is basically a land-bound and more mobile version of a Macrocannon.