And it is well possible that both sides are right, since, strictly speaking, an Imperial autogun is generally any type of automatic rifle, firing solid slugs accelerated by combustion of gunpowder charge. As such, there are great many models and patterns in existence, different in both internal mechanics of their action and the ammunition they use. It means that while some autoguns are backwater-colonies locally designed crude weapons, using blackpowder-filled cartridges and prone to jamming, the other autoguns may be high-tech products of AdMech factories, firing hypervelocity discarding-sabot needle-bullets, capable of easily punching through carapace armour.
Tl;dr, if the Lasgun is called a 'Flashlight' then the Autogun is called a 'Stapler'.
Most often a machine pistol or submachine gun, the Autopistol is a single-handed submachine gun (called the
Uzi Autopistol) which is frequently used by Chaos heretics (and on occasion, traitor guardsmen) and cultists who don't particularly care about accuracy or expenses and wish to be able to make noise and cause death at a close distance (the former is done better by an Autogun than a Lasgun) as they close in to use their swords. Quite fittingly, many of the autopistols manufactured by the Imperium are based off the MAC-10/MAC-11 weapon series.
Autopistols are still in massive use throughout the Imperium and can be found even on low-tech worlds. Like the larger Autogun it is a very easy to construct and usually available in large numbers. The autopistol is a common weapon amongst renegades, gang members, and lowly criminals, being as easy to use as it is to construct. They are not generally considered a military issue weapon, but are a favorite amongst many military veterans as a supplement for their standard lasgun or as a backup weapon, especially by the ones using unreliable melta- or plasma-weaponry. Some regiments, including the Cadian 8th, often equip all their troops with autopistols as sidearms, improving their combat firepower. Other commanders allow their troops to acquire spoils from the battlefield for their own use and autopistols are popular choices.
There are dozens of other Autogun models that have been created since, including more-advanced versions that use caseless ammunition. One common variety is an assault-rifle sized version formerly used by Imperial Guard regiments, known as the Agipinaa Type-II pattern Autogun (the one specifically noted to achieve stopping power on par with modern Imperial Guard-issue lasguns). While rather heavy at 6,2 kg (with loaded magazine), this gun fires powerful (but having somewhat heavy recoil) 8,25mm caliber rounds, accelerated to muzzle velocitiy of 825 meters per second while traveling through the autogun's 540mm (21,25 inches) long barrel.
Autoguns are commonly employed by pirates, rebel groups, Chaos cultists, Kriegers, Planetary Defense Forces, Hive Gangers, Adeptus Arbites and low-tech civilisations that are too underdeveloped to create even a simple Lasgun, which puts into perspective just how poor these people are. (Hey, that includes us...) On the Tabletop, they're basically Rule 63 versions of lasguns, with the same exact specs.
In Warhammer 40,000: Fire Warrior, the Stormtroopers used by the Guard detachment on-planet uses Autoguns that have been given special armor-piercing rounds (also known as "Man Stopper" rounds, featuring a penetrator-tip of hardened adamantium alloy embedded in each bullet) to improve their damage output, essentially putting them on-par with Hellguns. Paired with the weapon's fast fire rate, they're probably the earliest weapon you can reliably take down a Space Marine or Chaos Space Marine with, though clearly better options are available.
The Autocannon is the big-cheese of the Autogun family (and possibly related to the
88mm flack gun Bofors 40-57mm 20mm Hispano-Suiza GW couldn't tell which is which anyway), firing massive projectiles quickly enough that it can infatuate and butcher a group of Orks at the same time. Most commonly mounted on vehicles, but also seeing use in Imperial Guard heavy weapons teams, it possesses a frightening rate of fire and good armour penetration. Much like a heavy stubber, the autocannon proves that even older tech can work when scaled up in size. Before a certain temper tantrum and its aftermath, it used what were approximately up-scaled Heavy Bolter shells to literally kill anything. Basically, these autocannon shells were to 40k's autocannon shells what Baneblade cannons are to battle cannons. Yeah. By the way most modern cannons actually use advanced shells like this, suck it imperium.
The standard Autocannon makes a satisfying POM-POM-POM sound as it chews up targets up to four feet away. It hits at S7AP-1 and is a Heavy 2 weapon that deals D2, making it statistically better than the Heavy Bolter against everything except Toughness 4 and less models. The long-barreled Hydra variation is used on the Hydra Flak Tank, and is designed to serve as anti-air support but used to chew up any cocky infantry that gets too close. Nowadays it gives warning shots that may clip an enemy if that enemy is standing right in front of it and jumps up and down screaming "SHOOT ME" (and even then might miss). Fortunately, it has an additional two feet of range, so while it only has one job, it tends to do it pretty well.
Then there is the Reaper variant, which only the Chaos Space Marines get because Assault Cannons were discovered after the Horus Heresy, and everybody Imperial promptly thought they were cooler than the Reaper Autocannon. The reaper is an infantry-portable twin-linked Autocannon that wants to put its shells in your face at 36" or less. The reaper is effective against light vehicles and monsters, but the Imperials switched to the other gun for its boons against infantry. The current Imperial gun is mostly popular due to it's reliability and durability, capable of operation for years without much care even if someone used it as a club. By comparison, the reaper assault cannon needs it's barrels to be replaced after each battle or else it loses reliability or even explodes (maybe the admech were drunk that day).
Then at some point, the Traitor Legions and their Dark Mechanicus pals looked at the Reaper Autocannon and asked, "How can we make this even more rapey?" So they came up with the Helstorm Autocannon, which apparently can only be fitted to vehicles and aircraft such as the Hellblade due to its sheer rate of fire. It has the same profile as the Reaper except for firing an extra shot per attack and adding delicious Rending because fuck assault cannons. Now if only GW would let the forces of Chaos get their collective shit together and replace every vehicle mounted heavy bolter with S7 AP4 Heavy 3, Twin-linked, Rending.
Also because Chaos likes to add daemons to things, and daemons make things goofy, Chaos Space Marines have access to another vehicle-mounted variant, the Hades Autocannon, which bafflingly can only be mounted onto a dinobot (probably because it's propelled by warp-flame or something). Fieled onto a Heldrake for air support or in pairs on a Forgefiend for heavy support, the Hades Autocannon (R36", S8, AP4, Heavy 4, pinning) suffers the Reaper's slightly gimped range compared to the vanilla autocannon, but is slightly stronger and can pin units (but don't count on pinning too much); while it's not twin-linked like the reaper, having double the firepower more than compensates. A Forgefiend can mulch most infantry short of Terminators, pounding through power armour on sheer weight and power of fire, can make most Monstrous Creatures' lives flash before their eyes, and can hurt even a Land Raider or Monolith. It's
almost really a shame that the average Forgefiend isn't known for being a phenomenal shot.
Back when the Emperor still walked, the Imperium was capable of developing new and improved weapons, and the Accelerator Autocannon was one of those. Basically a cross between the Autocannon and a Rail Gun, the Accelerator Autocannon coupled a high rate of fire with a powerful shell and high accuracy. It shares it name with the Accelerator Cannon used on the Fellblade. Which would imply that this is a downsized version.
Currently the Accelerator Autocannon is exclusively mounted on the main variant of the Sicaran Battle Tank. Each Sicaran has two of them. Why they don't bother mounting them on the more advanced Dreadnaughts is because they don't know how or due to lazyness.
Onslaught Gatling Canon
The latest weapon for the Adeptus Astartes, and currently restricted to use as a secondary weapon on the Repulsor Hover Tank and Redemptor Dreadnought. It has the strength and armour penetration of a heavy bolter at two thirds the range and twice the rate of fire.
Heavy Onslaught Gatling Cannon
Maximum dakka for the Astartes, the Heavy Onslaught is the primary weapon of the Repulsor Hover Tank and Redemptor Dreadnought. It has the same strength and armour penetration as its smaller brother, but a 30" range and an incredible 12 shots. Interestingly inferior to the Punisher gatling cannon against everything that doesn't have heavy (2+) armour.
The Assault cannon is an Autogun with an outrageous rate of fire, meaning it has to have rotating barrels to stop them from melting. Although it falls far short of it's terrifying fluffy firepower on tabletop, firing 4 shots compared to the 10 and 20 shots of imperial Gatling cannons. It also fires unique, diamond-hard rounds at significantly increased velocity, resulting in far greater stopping power and penetration. The upgraded weapons system was found post-Heresy, meaning that Chaos doesn't get these meat-grinders (although Obliterators do). Primarily used by Space Marines as anti-infantry weaponry on Terminators, Dreadnoughts, and various other vehicles and aircraft. The assault cannon might actually be a stub-weapon, as some art shows it ejecting spent casings. Only War and several other sources show that there is a difference. Auto-weapons are (usually) caseless and can be anything from merely caseless, chemically-propelled rounds, to railrifles and gravitic-accelerated projectiles. This is also why Macrocannons are auto-weapons, as their shells are magnetically propelled. Of course, knowing the Mechanicus, there are probably examples of both auto-weapons and stub-weapons for all solid-projectile weapons of the Imperium.
If it was a laser weapon, it would be to Multilasers something like what a Hellgun is to a Lasgun.
It should probably have been named Rotor Gun instead, to avoid insulting the true cannons. The ancestor (feeble grandparent) of the Assault Cannon, firing smaller-caliber, less-capable ammunition and to date only seen in 30k. Unfortunately it is much weaker than its more recognizable descendant, with only half the stopping power (in fact it is on par with the standard Autogun and outclassed by the Heavy Stubber) and much less armour-piercing ability, despite having the same shot output most of the time. About the only advantage it has over the Assault Cannon is the fact that it is man-portable by both Power-Armoured Astartes and unaugmented humans, whereas the Assault Cannon requires the user to wear Terminator armour or a vehicle mounting. Based on the stats, it presumably fires similar rounds to an autogun (which is analogous to a modern battle rifle) but at a much higher cyclic rate, so it probably has some similarity to an M134 minigun.
Punisher Gatling Cannon
The Punisher Gatling Cannon is the primary armament of the Leman Russ Punisher tank and one of the Vulture Gunship's variants. A recent edition to the Imperial Guard armory, the Punisher Gatling cannon unleashes a torrent of anti-infantry firepower and is among the fastest-firing weapons in the Imperial arsenal.
The most dakka in the game that isn't the Titan mounted Vulcan Mega-Bolter. In fact, so much it doesn't go "dakka, dakka" it goes BRRRRRRRRRRRRRRRT. Able to churn out more shots than a squad of Tactical Marines at even greater strength, this baby will melt down any block of infantry it comes across and can even threaten Monstrous Creatures by the sheer volume of fire they put out. Also has a kid brother in the form of the Taurox Gatling Cannon, which has less strength and half the shots.
The big cheese of the Autogun family without going full on Titan. The Battle cannon is a larger and heavier version of the autocannon, its size restricting its use to vehicles only. It is the primary weapon of the Leman Russ Battle Tank, where its explosive shells can decimate both infantry and other armor. It is also common armament on Imperial Knights, though for these mighty machines are used special Rapid Fire Battle Cannons with improved rate of fire. Due to it being of Autogun in function, it has a wide variation of different ammunition that it can use. such as:
High Explosive: The standard round fired by Leman Russ battle cannons, HE shells like the Leman Russ Mk4 G4 round contain a highly explosive material such as Fyceline which detonates upon impact with the target. Since a high velocity is not necessary for the shell to work, a small amount of propellant allows for a larger amount of explosive material than in other shells. The explosion causes a blastwave lethal to anyone close by and shatters the thin shell casing into deadly high-speed shrapnel, making them deadly when used against infantry and light vehicles. While the sheer size of the blast can cause minor damage to armored vehicles, even stun or kill the crew within, HE shells lack the penetrative power of true anti-tank shells.
Anti-Tank/Armour Piercing: Anti-tank or armor piercing shells like the standard Leman Russ Mk12 G4 round are used to destroy hardened targets such as enemy tanks or bunkers. They consist of a solid round topped with an adamantium tip covered by a soft metal cap. A large propellant charge launches the round at high velocities, where upon impact the metal cap melts and creates a "sticking" effect so that the adamantium tip does not slide off of sloped armor or break. Most AP shells cause damage through kinetic energy, the sheer violence of a penetrating hit causing spalling within the enemy tank's interior to damage internal systems and kill crew. Others include a small high explosive charge which detonates upon impact, causing additional secondary damage.
Infernus: Inferno shells like the standard Leman Russ Mk7 G4 round, also known as incendiary, phosphorine or thermite shells, work in similar principle to HE shells. However instead of an explosive charge these shells are filled with a combustible substance which instantly is scattered upon impact. The substance burns instantly and is particularly deadly when used against infantry.
Smoke: Smoke shells are used to create an instant smoke screen, hiding the tank or other friendly forces from enemy observations.
Hunter: Hunter shells are very rare tank rounds which can be fired by a battle cannon or Conqueror cannon. They contain a small logic-engine similar to the one found on Hunter-Killer Missiles which locks onto a target and directs the path of the shell towards it. Just before impact the shell's Machine Spirit causes it to rise above and hit the enemy vehicle on it's thinner top armor. Only ever produced on the Forge World Tigrus, the knowledge to construct Hunter shells was lost when the world was overrun by the Orks. Most tank crews will therefore never even see a Hunter shell, much less have the honor of firing one.
Strapped to the mighty Reaver Battle Titan and above, this is the weapon you field when you need the biggest dakka the Imperium of Man has to offer, it's basically an Assault Cannon, except that it fires Battle Cannon shells rather than bullets, yeah... this is what you get if you thought about the Schwerer Gustav using Gatling Technology. Now if only they had some kind of Macro Gatling, ridiculous as that would be.
Galting Blasters can be mounted on the weapon limbs of Reaver and Warlord Battle Titans and the carapace mounts on Imperator Titans. It is too large to be fitted to Warhound Scout Titans however.
The Biggest of the Big. 'Macrocannon' seems to be a catch-all for any auto-type weapon larger than a Gatling-Blaster, ranging from fortress-mounted field artillery to the literally apocalyptic, cathedral-sized weapons found on voidcraft. As is clearly evident, it causes a quantity of Rape proportional to its size, but even the smallest land-based Macrocannons are capable of laying waste to mostly everything, including flyers. It is at its basest an autocannon that fires bullets ranging in size from that of a man all the way up to the size of a Baneblade, depending on the weapon's calibre (no, seriously), and since this is the Imperium, instead of an automatic reloader, they need dozens of slaves to move each bullet for the ship-mounted Macrocannons (heretical theories suggest this is either because it is actually cheaper for the Imperium, which is overloaded with humans and not resources, or because they are stockpiling resources, or they are cutting down on chances of daemonic incursions through humans by putting more of them in the killzone, or they are testing to see just how far people will comply with slave labor in a totalitarian state, or - most heretical of all - some suggest it is a bureaucratic screw-up with paperwork or that the AdMech doesn't know how to repair the loading cranes). Provided yields for these weapons can go from 42 exajoules (about 5.297 times more powerful than the most powerful earthquake ever recorded; a 42 exajoule earthquake would be approximately magnitude 9.98) right down to the measly 50 tetrajoules...*sigh* Games Workshop never fails to surprise us. Seriously believe us, we know that tetrajoules isn't an official unit of measurement, but since tetra is Latin for four this essentially gives us....4 joules of power....which is weaker then a human punch or a flashlight.... Don't believe us? We got that from Rogue Trader rpg: BattleFleet Koronus pg. 31 & 20 which is quote on quote:
- "Look at her, son. Isn’t she a beauty? Over two hundred Vulcan mega-bolter defence turrets, fifteen tetrajoule Sunsear las-broadsides, prow plating ten metres thick, the finest auspex masts in the battlefleet… And the lines on her! Fluted prow, elegant statuary… those xenos scum won’t know what hit them!” – Bosun Phineas Jhule tempts fate at the embarkation of the Fire of Heaven
- "The Avenger dates from an earlier period of fleet tactics, when, squadrons of grand cruisers were employed as “line-breakers.” Traditionally, they were thrown into the midst of massive fleet engagements, soaking up enemy fire while racing into the middle of enemy formations, then crushing their opponents at short range with tetrajoules of energy from their oversized broadsides."
Yeah...we in /tg/ aren't sure whether this was intentional or a gross example of a severe typo. So...um....FEAR THE 60 JOULE BROADSIDE BATTERIES! Jokes aside, if we use the picture to the right as a reference for size, and estimate the shell as a solid slug of density equivalent to lead, launched at a planet from geosynchronous orbit above an Earth-like planet (36,000km), you're looking at somewhere in the region of 50 Tera-Joules of energy when it strikes the ground, or slightly less than the Little Boy dropped on Hiroshima (and that's just from gravity, not including launch energy). About fifty or so of the land-based Macrocannons would equate to one ship-mounted Macrocannon, or one point of firepower in Battlefleet Gothic. Oh yes.