Any idea of what the stats for a GAU-8 Autocannon might be? [Archive] - Wizards Community

Any idea of what the stats for a GAU-8 Autocannon might be? [Archive] - Wizards Community

Post/Author/DateTime Post
Voran
03-07-07, 04:51 AM http://en.wikipedia.org/wiki/GAU-8_Avenger

Any idea what sorta d20 stats for DnD this might look like? Figured it'd make a nice weapon for a BBEG I'm tinkering with. Afterall, why use a smokepowder weapon when you can use the autocannon from a A-10?
molten_dragon
03-07-07, 06:55 AM I would probably treat it as a line or cone effect with a very long range (a few hundred feet). Damage is hard to estimate. Those things are incredibly powerful guns, but probably not as powerful as some magical effects. Something in the range of 10d6-15d6 would probably be good. I would also have it ignore nonmagical armor and maybe destroy it as well.
Watchman
03-07-07, 07:16 AM Save Or Die (Reflex ?) sounds like a better approach. Seriously. That monster is made to rip tanks apart, even if through the thinner topside. I don't care if it's a big dragon, unless it has like total invulnerability to nonmagical attacks or something it's not going to survive a direct burst as anything else than so much mincemeat.
Lotus Crane
03-07-07, 09:01 AM I'm sure one of the D20 Modern books already has stats for it, or at least a comparable fictional counterpart.

Save Or Die (Reflex ?) sounds like a better approach. Seriously. That monster is made to rip tanks apart, even if through the thinner topside. I don't care if it's a big dragon, unless it has like total invulnerability to nonmagical attacks or something it's not going to survive a direct burst as anything else than so much mincemeat.
Trying to run D&D according to the rules of reality almost never makes sense. We're talking about a world where a terminal velocity fall from sub-orbital heights and full immersion in lava both cap out at 20d6 damage (avg 70). Any D&D character at double-digit levels would be the equivalent of a "superhero" in the real world; ie no real human beings have ever reached that level of personal ability (even legends like Alexander the Great or Bruce Lee, would all be the equivalent of 9th level or lower if transported to your average D&D world).

In such a setting, an old or older dragon who can regularly defeat such characters, would probably eat a gatling blast and ask for seconds.
Dragonteuthis
03-07-07, 10:22 AM Not to mention that you've got arrows that can effectively penetrate Full Plate armor, a fact that runs completely smack against history. With that kind of assumption in the base game, the penetration capabilities of a bullet are way out of place, and make for some very confusing additons.

Good luck though.
Stormonu
03-07-07, 10:58 AM It's be easier to stat out this cannon than you think. It's used to punch through tank armor, so it's got to, on average do more than 20 points of damage (Hardness of a M1 tank). So we're looking at about 6d6 damage (ave. 21 damage) for the gun, minimum. I'd put it at about 8d6 or so (ave. 28 damage) to account for the damage it can actually do to the tank itself.
jacobi289
03-07-07, 11:25 AM must be size huge or bigger to wield
range increment: 1000 (accurate to 10 feet at 1 mile)
is a ranged touch attack (ignores armor AC)
counts as adamantine and magical for purposes of overcoming DR
if a 10 foot square of 3" iron had hardness 10 and 90 hp, and this cannon would make mincemeat of it in 6 seconds, I'd put damage in the 15d6 area.
attacking with it counts as a full attack action.
has enough ammo for 2 attacks, after which reloading is a full round action
Tyraxus
03-07-07, 12:44 PM Not to mention that you've got arrows that can effectively penetrate Full Plate armor, a fact that runs completely smack against history.

Not to get into a history argument, but...

Weren't English longbows quite effective against armoured knights (notably of the French variety)?

EDIT: Maybe not quite as effective as I'd thought, but still able to get to the man beneath the steel. And I know the crossbow was effective, it's supposedly the only weapon of war whose use was outlawed by the Pope himself.
Bhaal006
03-07-07, 12:53 PM this is absolutely ridiculous(my word for the day) the fact that you'd want to stat this out is some sort of thing i can't even begin to relate in an intelligible manner.
this thing would tear a dragon to shreds, the damage would be like 20d20, on a failed save.
Melpomene
03-07-07, 12:59 PM Make it equitable to a spell. This is best, as it allows you to controll your CR and overall power rating. For example, having it be a Magic Missile (5d4+5) wouldn't be unreasonable. You could certainly ramp the damage up based on other spells, of course, although force (or sonic) damage might be best to avoid characters with energy resistance.
narukagami
03-07-07, 02:37 PM You'd get better results from the d20 Modern board.
Stormonu
03-07-07, 03:37 PM if a 10 foot square of 3" iron had hardness 10 and 90 hp, and this cannon would make mincemeat of it in 6 seconds, I'd put damage in the 15d6 area.

:rofl: You realize according to d20 modern a M1 Abrams has hardness 20 and 64 hit points for the entire tank. To me, that just proves that d20 modern is junk, btw.
FrostWolf
03-07-07, 05:25 PM :rofl: You realize according to d20 modern a M1 Abrams has hardness 20 and 64 hit points for the entire tank. To me, that just proves that d20 modern is junk, btw.

Agreed. But anyways....

The standard ammunition mixture for anti-armor use is a four-to-one mix of PGU-14/B Armor-Piercing Incendiary (API), with a projectile weight of about 15.0 oz (425 grams or 6,560 grains) and PGU-13/B High Explosive Incendiary (HEI) rounds, with a projectile weight of about 12.7 oz (360 grams). The PGU-14/B round incorporates a depleted uranium penetrator. The Avenger is lethal against tanks and any other armored vehicle. The use of the depleted-uranium round is controversial, with some reports linking its use to health problems among both survivors of DUP attacks and servicemen involved in the loading and handling of the rounds. Residual DU in soil (and thus water-tables) has also been implicated in a sharp spike in birth defects observed in certain areas of Iraq immediately after the Gulf War.

A very important innovation in the design of the GAU-8/A shells is the use of aluminium alloy cases in place of the traditional steel or brass. This alone adds 30% to ammunition capacity for a given weight. The shells also have plastic driving bands to improve barrel life. They are imposing to examine and handle, measuring 11.4 in (290 mm) in length and weighing 1.53 lb (694 g) or more. (Spick, 2000, p. 44).

Originally, the Avenger's rate of fire was switchable between 1,800 rounds per minute (RPM) and 4,200 RPM. In later modifications, the 4,200 RPM rate of fire was replaced with a slightly lower 3,900 RPM. In practice, the cannon is limited to one and two-second bursts to avoid overheating and conserve ammunition; barrel life is also a factor, since the USAF has specified a minimum 21,000-round life for each set of barrels. It is also said that this is to deal with the substantial deceleration of the plane that results from firing (see below for details).

SO AS I SEE IT!

3900/60=65 rounds a second. So 130 for a two second burst. Anti-Armor rounds, that much ammo would tax even a spell at that point. So armor would be useless. Hope you have a HIGH dex.

DMG says An automatic rifle is 2d8 and 30 rounds that you can spray an area with (uses 10 rounds). anyone hit takes the weapons damage. But the tank buster would be using bigger shot and throwing more, so a two second burst would be about 13d10 with a reflex save of about 25~ish. (Yes, each round as 1d10 is my estimate.)

Also, anyone hit should take a fort save or risk becomming sick from the depleted uranium rounds.

And that's without enchanted ammo.
Voran
03-07-07, 06:14 PM Thanks for the replies all. I'm thinking comparing it to a breath weapon might be a good approach.

I'm thinking of a "Vulcan Raven" type BBEG lieutenant. The PCs would encounter said dude from afar, watching as he steps to the battlements of the beseiged BEG keep while the NPC army tries to batter down the walls, and unloads with his autocannon into the ranks of soldiers.
Jackmojo
03-07-07, 06:21 PM If I were looking for something like this I'd run it as doing a lightening bolt or a cone of cold (users choice) but as untyped (or perhaps bludgeoning) damage, probably make it a full round action to fire, so the poor PCs could at least try to out manuever him :) .

Jack
Melpomene
03-07-07, 06:34 PM Remember that untyping your damage for a spell is equivilant to increasing it's level by one. That is to say, a piercing lightning bolt would be a 4th level spell.

Also, as I assume your guy won't have wizard stats, you'll want to price a 'use activated' item that casts L-Bolt (or whatever), which is going to be very expensive.

For a command word L-bolt that deals 10d6 piercing, for instance, it's 72,000.
mightyix
03-07-07, 06:58 PM It's be easier to stat out this cannon than you think. It's used to punch through tank armor, so it's got to, on average do more than 20 points of damage (Hardness of a M1 tank). So we're looking at about 6d6 damage (ave. 21 damage) for the gun, minimum. I'd put it at about 8d6 or so (ave. 28 damage) to account for the damage it can actually do to the tank itself.

Not only does it punch through a tank - Hardness 20, but it eliminates ALL of it's hit points in a single attack.

Arguably the depleted uranium or tungsten projectiles the thing spews out ignore hardness when fired from the gun. They will go through pretty much anything they hit.

Mechanically, have the weapon use the Brilliant Energy mechanic from PHB, bypassing Armor, have it ignore object hardness as well, and assign an arbitrarily high number of d6 damage to the weapon. It carries 3000 or so rounds of ammunition on a standard A-10 loadout, for about 5 seconds of total fire. Figure it's got about 10 shots in it before it's out of ammo.

And at 19 feet long and weighing several tons (before ammunition), the GAU-8 can really only be wielded by a gargantuan creature as a 2 handed weapon.

Someone else suggested save or die, I'd just point out the massive damage rules and note that this thing almost always puts out more than 50 points of damage in a single shot. Putting it in the perspective of a 9th level spell damage cap.... 25d6 isn't unreasonable.
mightyix
03-07-07, 07:02 PM Agreed. But anyways....
Also, anyone hit should take a fort save or risk becomming sick from the depleted uranium rounds.

And that's without enchanted ammo.

You're buying hype. DU is harmless and every single time someone has tried to prove a link between DU and illness they've been unable to provide evidence sufficient for the Nuclear Regulatory Agency, FDA, and the Surgeon general to to change policies.

Besides, do you really want a game mechanic for a low DC sickness when you're dealing with a massive gun.
Watchman
03-07-07, 07:05 PM Wonder what the stats for a 120mm tank gun would look like, tho'... :D

Yes, I would keep it simple and make it Save Or Die as well.
Voran
03-08-07, 03:34 AM Also, anyone have suggestions on how I might verbally describe said Autocannon without making it immediately apparent its an autocannon?

I'm thinking at first view, he'll be far enough away that you won't notice the rotating barrels given the huge muzzle flashes going off.
Watchman
03-08-07, 07:13 AM Given the size of the muzzle blast the thing throws off, you can probably get it passed for a fire-hose for a while.

And I wanna know how the BBEG lieutenant doesn't fly off the wall due to the recoil. :D Firing that monster cannon appreaciably slows the A-10 down in flight, after all.
Southernskies
03-08-07, 07:39 AM Also, anyone have suggestions on how I might verbally describe said Autocannon without making it immediately apparent its an autocannon?

I'm thinking at first view, he'll be far enough away that you won't notice the rotating barrels given the huge muzzle flashes going off.

"The BBEG reaches down for his weapon of choice that looks like some sort of repeating crossbow... 10 feet long. Braced against the wall, a strange whirring noise can be heard until a unbroken line of fire and explosions reach out, scything through the nearest unit of your army. The unit itself ceases to exist, as hundreds of small explosions scatter debris and blood across a wide area. And then the device swings towards you..."
RealSorceror
03-08-07, 01:54 PM Sweet thread! I'm currently building a Dragon Mech (collosal+ steam powered machine), and I need some guns that can pack a punch.
The largest steam-powered cannon in this setting is the City Killer, which deals about 12d12 piercing, and has a range of out to 1,000ft. Granted, this weapon, and the power needed to fire it, are enormous.
Joush Mark
03-08-07, 03:01 PM The weapon fires so quickly that individual shots can't be seen for the weight of fire, and individual explosions are lost in the blast.

In operation, it's basically a death ray, sweeping over the battlefield and exploding anything it touches, shredding anything alive into burning meat and tearing apart anything that might seem to offer cover.

This is a 30mm autocannon. It's beyond human scale and the only thing that can hope to stand up to it is a hard point like a bunker or a modern battle tank across the thickest armor.

When they are working they really look like a death ray, an unbroken line that ruins anything it touches.

A dark figure stands on top of the battlements and lifts something larger then a wagon, bracing it across the wall before it suddenly burst into brilliant light. A glowing shaft of light leaps from the weapon and annihilates everything it touches, sweeping over the battlefield
ScipioX
03-08-07, 06:52 PM One projectile would kill just about any living thing on a direct hit. A hail of them would annihilate flesh and bone into a bloody mist.

A ray of destruction is pretty apt. I'd just call it a save or die line effect. Use a reflex save, something like DC 20 sounds about right.
Feroz
03-08-07, 11:08 PM Line effect Disintigrate.
Voran
03-08-07, 11:32 PM For High normal, and low-Epic levels, I've added a special quality to some heroes/villains, allowing for more comic-book like feats of strength. Effectively the ability gives you a 'virtual size boost'. You can be a medium sized creature, but with enough mods, have a virtual size of huge, gargantuan, colossal, whatever, which lets you have a not too obscene +modifier due to strength score, but lets you have an impressive modified lift/carry capacity. It also has an effect in terms of modifying your strength in opposed contests, giving you whatever positive benefit your virtual size would have.

Thus a medium sized dude can walk out carrying a 'fully loaded' nearly 2 ton autocannon, and fire it because in effect he's a gargantuan or larger creature.
Norsesmithy
03-09-07, 12:40 AM If a D20 Modern Remington 700 in .30-06 does 2d10 per shot, how much damage does a weapon that pushes a projectile more than 30 times heavier, 1.5 times as fast do?

Simple multiplication says we should see 67d10 (rounded down) per hit, but I would adhoc 15d10 per API hit, say 12d10 per HEI hit, line effect let us say that no more than 1/4 of the 130 shells in a 2 second burst can hit any one creature, and allow a reflex save for half (DC attack roll). This comes to a still ridiculous 432d10, reflex for half (almost 2600 average damage).

Just call it save or die.
Voran
03-14-07, 08:45 PM Upon further consideration, here's what I've come up with.

"Autocannon"

Functions as a breath weapon, with a 1-3 round recharge time, reflecting the time where the 'ammo' is magically replenished. Line or Cone of Effect (still figuring ranges).

The cannon does 3d6x20 damage per manifestation to anything stuck in the area/line of effect. However, treat as 20 individual 3d6 attacks for purposes of Damage Reduction or Hardness, with the qualifier that even if negated by DR/Hardness, it does at least 1 pt of damage per attack (so minimum of 20 pts). Creatures hit by the cannon also suffer a simultaneous Bull Rush type effect, as if hit by a Medium Creature with a strength rating equal to Half the total damage rolled. For purposes of hit, assume the effect continues to push past the initial step and follows the target until momentum runs out.

I'm thinking this'll give the chunky salsa effect for typical targets, but for hardened magical targets while they may not get severely damaged by the actual rounds, they'll usually get knocked away by the force of the fire.

Reflex save for Half. DC...I dunno yet.

Too wimpy for a high-normal/low-epic encounter?
mugguod
03-14-07, 09:08 PM No idea about the number of damge dice, but had one thought:

Fires only in a straight line using a standard action
To spray a cone requires full-round action, and uses up more ammo.
Full_Metal_Samurai
03-14-07, 09:22 PM 180d10... cause its 1,800 rounds per minute then it would be 180 rounds per six seconds.

Though perhaps a more balanced stat would be 7d10, line/area with no attack penalty or a cone/area with a -4 attack penalty, 20/x4, 1000 ft. range either class as ballistic or peircing (depending if you're putting ballistic as a damage type in your game).
Tom Peters
03-14-07, 09:53 PM You have to be kidding. A single hit with the weapon will kill anything large size or smaller and ruin the day of anything larger (and the cannon wont hit just once). A Wall of Force might stop it, but worn armor would be utterly useless.

Dont mix technology and fantasy.

Mad Dog
ScipioX
03-14-07, 10:33 PM 1d10 and 3d6 per hit is simply pathetic. These are not mere bullets; they're CANNON shells. A elephant gun round can kill an elephant... which has 104 hp. These are orders of magnitude more powerful.

Post/Author/DateTime	Post
Voran 03-07-07, 04:51 AM	http://en.wikipedia.org/wiki/GAU-8_Avenger Any idea what sorta d20 stats for DnD this might look like? Figured it'd make a nice weapon for a BBEG I'm tinkering with. Afterall, why use a smokepowder weapon when you can use the autocannon from a A-10?
molten_dragon 03-07-07, 06:55 AM	I would probably treat it as a line or cone effect with a very long range (a few hundred feet). Damage is hard to estimate. Those things are incredibly powerful guns, but probably not as powerful as some magical effects. Something in the range of 10d6-15d6 would probably be good. I would also have it ignore nonmagical armor and maybe destroy it as well.
Watchman 03-07-07, 07:16 AM	Save Or Die (Reflex ?) sounds like a better approach. Seriously. That monster is made to rip tanks apart, even if through the thinner topside. I don't care if it's a big dragon, unless it has like total invulnerability to nonmagical attacks or something it's not going to survive a direct burst as anything else than so much mincemeat.
Lotus Crane 03-07-07, 09:01 AM	I'm sure one of the D20 Modern books already has stats for it, or at least a comparable fictional counterpart. Save Or Die (Reflex ?) sounds like a better approach. Seriously. That monster is made to rip tanks apart, even if through the thinner topside. I don't care if it's a big dragon, unless it has like total invulnerability to nonmagical attacks or something it's not going to survive a direct burst as anything else than so much mincemeat. Trying to run D&D according to the rules of reality almost never makes sense. We're talking about a world where a terminal velocity fall from sub-orbital heights and full immersion in lava both cap out at 20d6 damage (avg 70). Any D&D character at double-digit levels would be the equivalent of a "superhero" in the real world; ie no real human beings have ever reached that level of personal ability (even legends like Alexander the Great or Bruce Lee, would all be the equivalent of 9th level or lower if transported to your average D&D world). In such a setting, an old or older dragon who can regularly defeat such characters, would probably eat a gatling blast and ask for seconds.
Dragonteuthis 03-07-07, 10:22 AM	Not to mention that you've got arrows that can effectively penetrate Full Plate armor, a fact that runs completely smack against history. With that kind of assumption in the base game, the penetration capabilities of a bullet are way out of place, and make for some very confusing additons. Good luck though.
Stormonu 03-07-07, 10:58 AM	It's be easier to stat out this cannon than you think. It's used to punch through tank armor, so it's got to, on average do more than 20 points of damage (Hardness of a M1 tank). So we're looking at about 6d6 damage (ave. 21 damage) for the gun, minimum. I'd put it at about 8d6 or so (ave. 28 damage) to account for the damage it can actually do to the tank itself.
jacobi289 03-07-07, 11:25 AM	must be size huge or bigger to wield range increment: 1000 (accurate to 10 feet at 1 mile) is a ranged touch attack (ignores armor AC) counts as adamantine and magical for purposes of overcoming DR if a 10 foot square of 3" iron had hardness 10 and 90 hp, and this cannon would make mincemeat of it in 6 seconds, I'd put damage in the 15d6 area. attacking with it counts as a full attack action. has enough ammo for 2 attacks, after which reloading is a full round action
Tyraxus 03-07-07, 12:44 PM	Not to mention that you've got arrows that can effectively penetrate Full Plate armor, a fact that runs completely smack against history. Not to get into a history argument, but... Weren't English longbows quite effective against armoured knights (notably of the French variety)? EDIT: Maybe not quite as effective as I'd thought, but still able to get to the man beneath the steel. And I know the crossbow was effective, it's supposedly the only weapon of war whose use was outlawed by the Pope himself.
Bhaal006 03-07-07, 12:53 PM	this is absolutely ridiculous(my word for the day) the fact that you'd want to stat this out is some sort of thing i can't even begin to relate in an intelligible manner. this thing would tear a dragon to shreds, the damage would be like 20d20, on a failed save.
Melpomene 03-07-07, 12:59 PM	Make it equitable to a spell. This is best, as it allows you to controll your CR and overall power rating. For example, having it be a Magic Missile (5d4+5) wouldn't be unreasonable. You could certainly ramp the damage up based on other spells, of course, although force (or sonic) damage might be best to avoid characters with energy resistance.
narukagami 03-07-07, 02:37 PM	You'd get better results from the d20 Modern board.
Stormonu 03-07-07, 03:37 PM	if a 10 foot square of 3" iron had hardness 10 and 90 hp, and this cannon would make mincemeat of it in 6 seconds, I'd put damage in the 15d6 area. :rofl: You realize according to d20 modern a M1 Abrams has hardness 20 and 64 hit points for the entire tank. To me, that just proves that d20 modern is junk, btw.
FrostWolf 03-07-07, 05:25 PM	:rofl: You realize according to d20 modern a M1 Abrams has hardness 20 and 64 hit points for the entire tank. To me, that just proves that d20 modern is junk, btw. Agreed. But anyways.... The standard ammunition mixture for anti-armor use is a four-to-one mix of PGU-14/B Armor-Piercing Incendiary (API), with a projectile weight of about 15.0 oz (425 grams or 6,560 grains) and PGU-13/B High Explosive Incendiary (HEI) rounds, with a projectile weight of about 12.7 oz (360 grams). The PGU-14/B round incorporates a depleted uranium penetrator. The Avenger is lethal against tanks and any other armored vehicle. The use of the depleted-uranium round is controversial, with some reports linking its use to health problems among both survivors of DUP attacks and servicemen involved in the loading and handling of the rounds. Residual DU in soil (and thus water-tables) has also been implicated in a sharp spike in birth defects observed in certain areas of Iraq immediately after the Gulf War. A very important innovation in the design of the GAU-8/A shells is the use of aluminium alloy cases in place of the traditional steel or brass. This alone adds 30% to ammunition capacity for a given weight. The shells also have plastic driving bands to improve barrel life. They are imposing to examine and handle, measuring 11.4 in (290 mm) in length and weighing 1.53 lb (694 g) or more. (Spick, 2000, p. 44). Originally, the Avenger's rate of fire was switchable between 1,800 rounds per minute (RPM) and 4,200 RPM. In later modifications, the 4,200 RPM rate of fire was replaced with a slightly lower 3,900 RPM. In practice, the cannon is limited to one and two-second bursts to avoid overheating and conserve ammunition; barrel life is also a factor, since the USAF has specified a minimum 21,000-round life for each set of barrels. It is also said that this is to deal with the substantial deceleration of the plane that results from firing (see below for details). SO AS I SEE IT! 3900/60=65 rounds a second. So 130 for a two second burst. Anti-Armor rounds, that much ammo would tax even a spell at that point. So armor would be useless. Hope you have a HIGH dex. DMG says An automatic rifle is 2d8 and 30 rounds that you can spray an area with (uses 10 rounds). anyone hit takes the weapons damage. But the tank buster would be using bigger shot and throwing more, so a two second burst would be about 13d10 with a reflex save of about 25~ish. (Yes, each round as 1d10 is my estimate.) Also, anyone hit should take a fort save or risk becomming sick from the depleted uranium rounds. And that's without enchanted ammo.
Voran 03-07-07, 06:14 PM	Thanks for the replies all. I'm thinking comparing it to a breath weapon might be a good approach. I'm thinking of a "Vulcan Raven" type BBEG lieutenant. The PCs would encounter said dude from afar, watching as he steps to the battlements of the beseiged BEG keep while the NPC army tries to batter down the walls, and unloads with his autocannon into the ranks of soldiers.
Jackmojo 03-07-07, 06:21 PM	If I were looking for something like this I'd run it as doing a lightening bolt or a cone of cold (users choice) but as untyped (or perhaps bludgeoning) damage, probably make it a full round action to fire, so the poor PCs could at least try to out manuever him :) . Jack
Melpomene 03-07-07, 06:34 PM	Remember that untyping your damage for a spell is equivilant to increasing it's level by one. That is to say, a piercing lightning bolt would be a 4th level spell. Also, as I assume your guy won't have wizard stats, you'll want to price a 'use activated' item that casts L-Bolt (or whatever), which is going to be very expensive. For a command word L-bolt that deals 10d6 piercing, for instance, it's 72,000.
mightyix 03-07-07, 06:58 PM	It's be easier to stat out this cannon than you think. It's used to punch through tank armor, so it's got to, on average do more than 20 points of damage (Hardness of a M1 tank). So we're looking at about 6d6 damage (ave. 21 damage) for the gun, minimum. I'd put it at about 8d6 or so (ave. 28 damage) to account for the damage it can actually do to the tank itself. Not only does it punch through a tank - Hardness 20, but it eliminates ALL of it's hit points in a single attack. Arguably the depleted uranium or tungsten projectiles the thing spews out ignore hardness when fired from the gun. They will go through pretty much anything they hit. Mechanically, have the weapon use the Brilliant Energy mechanic from PHB, bypassing Armor, have it ignore object hardness as well, and assign an arbitrarily high number of d6 damage to the weapon. It carries 3000 or so rounds of ammunition on a standard A-10 loadout, for about 5 seconds of total fire. Figure it's got about 10 shots in it before it's out of ammo. And at 19 feet long and weighing several tons (before ammunition), the GAU-8 can really only be wielded by a gargantuan creature as a 2 handed weapon. Someone else suggested save or die, I'd just point out the massive damage rules and note that this thing almost always puts out more than 50 points of damage in a single shot. Putting it in the perspective of a 9th level spell damage cap.... 25d6 isn't unreasonable.
mightyix 03-07-07, 07:02 PM	Agreed. But anyways.... Also, anyone hit should take a fort save or risk becomming sick from the depleted uranium rounds. And that's without enchanted ammo. You're buying hype. DU is harmless and every single time someone has tried to prove a link between DU and illness they've been unable to provide evidence sufficient for the Nuclear Regulatory Agency, FDA, and the Surgeon general to to change policies. Besides, do you really want a game mechanic for a low DC sickness when you're dealing with a massive gun.
Watchman 03-07-07, 07:05 PM	Wonder what the stats for a 120mm tank gun would look like, tho'... :D Yes, I would keep it simple and make it Save Or Die as well.
Voran 03-08-07, 03:34 AM	Also, anyone have suggestions on how I might verbally describe said Autocannon without making it immediately apparent its an autocannon? I'm thinking at first view, he'll be far enough away that you won't notice the rotating barrels given the huge muzzle flashes going off.
Watchman 03-08-07, 07:13 AM	Given the size of the muzzle blast the thing throws off, you can probably get it passed for a fire-hose for a while. And I wanna know how the BBEG lieutenant doesn't fly off the wall due to the recoil. :D Firing that monster cannon appreaciably slows the A-10 down in flight, after all.
Southernskies 03-08-07, 07:39 AM	Also, anyone have suggestions on how I might verbally describe said Autocannon without making it immediately apparent its an autocannon? I'm thinking at first view, he'll be far enough away that you won't notice the rotating barrels given the huge muzzle flashes going off. "The BBEG reaches down for his weapon of choice that looks like some sort of repeating crossbow... 10 feet long. Braced against the wall, a strange whirring noise can be heard until a unbroken line of fire and explosions reach out, scything through the nearest unit of your army. The unit itself ceases to exist, as hundreds of small explosions scatter debris and blood across a wide area. And then the device swings towards you..."
RealSorceror 03-08-07, 01:54 PM	Sweet thread! I'm currently building a Dragon Mech (collosal+ steam powered machine), and I need some guns that can pack a punch. The largest steam-powered cannon in this setting is the City Killer, which deals about 12d12 piercing, and has a range of out to 1,000ft. Granted, this weapon, and the power needed to fire it, are enormous.
Joush Mark 03-08-07, 03:01 PM	The weapon fires so quickly that individual shots can't be seen for the weight of fire, and individual explosions are lost in the blast. In operation, it's basically a death ray, sweeping over the battlefield and exploding anything it touches, shredding anything alive into burning meat and tearing apart anything that might seem to offer cover. This is a 30mm autocannon. It's beyond human scale and the only thing that can hope to stand up to it is a hard point like a bunker or a modern battle tank across the thickest armor. When they are working they really look like a death ray, an unbroken line that ruins anything it touches. A dark figure stands on top of the battlements and lifts something larger then a wagon, bracing it across the wall before it suddenly burst into brilliant light. A glowing shaft of light leaps from the weapon and annihilates everything it touches, sweeping over the battlefield
ScipioX 03-08-07, 06:52 PM	One projectile would kill just about any living thing on a direct hit. A hail of them would annihilate flesh and bone into a bloody mist. A ray of destruction is pretty apt. I'd just call it a save or die line effect. Use a reflex save, something like DC 20 sounds about right.
Feroz 03-08-07, 11:08 PM	Line effect Disintigrate.
Voran 03-08-07, 11:32 PM	For High normal, and low-Epic levels, I've added a special quality to some heroes/villains, allowing for more comic-book like feats of strength. Effectively the ability gives you a 'virtual size boost'. You can be a medium sized creature, but with enough mods, have a virtual size of huge, gargantuan, colossal, whatever, which lets you have a not too obscene +modifier due to strength score, but lets you have an impressive modified lift/carry capacity. It also has an effect in terms of modifying your strength in opposed contests, giving you whatever positive benefit your virtual size would have. Thus a medium sized dude can walk out carrying a 'fully loaded' nearly 2 ton autocannon, and fire it because in effect he's a gargantuan or larger creature.
Norsesmithy 03-09-07, 12:40 AM	If a D20 Modern Remington 700 in .30-06 does 2d10 per shot, how much damage does a weapon that pushes a projectile more than 30 times heavier, 1.5 times as fast do? Simple multiplication says we should see 67d10 (rounded down) per hit, but I would adhoc 15d10 per API hit, say 12d10 per HEI hit, line effect let us say that no more than 1/4 of the 130 shells in a 2 second burst can hit any one creature, and allow a reflex save for half (DC attack roll). This comes to a still ridiculous 432d10, reflex for half (almost 2600 average damage). Just call it save or die.
Voran 03-14-07, 08:45 PM	Upon further consideration, here's what I've come up with. "Autocannon" Functions as a breath weapon, with a 1-3 round recharge time, reflecting the time where the 'ammo' is magically replenished. Line or Cone of Effect (still figuring ranges). The cannon does 3d6x20 damage per manifestation to anything stuck in the area/line of effect. However, treat as 20 individual 3d6 attacks for purposes of Damage Reduction or Hardness, with the qualifier that even if negated by DR/Hardness, it does at least 1 pt of damage per attack (so minimum of 20 pts). Creatures hit by the cannon also suffer a simultaneous Bull Rush type effect, as if hit by a Medium Creature with a strength rating equal to Half the total damage rolled. For purposes of hit, assume the effect continues to push past the initial step and follows the target until momentum runs out. I'm thinking this'll give the chunky salsa effect for typical targets, but for hardened magical targets while they may not get severely damaged by the actual rounds, they'll usually get knocked away by the force of the fire. Reflex save for Half. DC...I dunno yet. Too wimpy for a high-normal/low-epic encounter?
mugguod 03-14-07, 09:08 PM	No idea about the number of damge dice, but had one thought: Fires only in a straight line using a standard action To spray a cone requires full-round action, and uses up more ammo.
Full_Metal_Samurai 03-14-07, 09:22 PM	180d10... cause its 1,800 rounds per minute then it would be 180 rounds per six seconds. Though perhaps a more balanced stat would be 7d10, line/area with no attack penalty or a cone/area with a -4 attack penalty, 20/x4, 1000 ft. range either class as ballistic or peircing (depending if you're putting ballistic as a damage type in your game).
Tom Peters 03-14-07, 09:53 PM	You have to be kidding. A single hit with the weapon will kill anything large size or smaller and ruin the day of anything larger (and the cannon wont hit just once). A Wall of Force might stop it, but worn armor would be utterly useless. Dont mix technology and fantasy. Mad Dog
ScipioX 03-14-07, 10:33 PM	1d10 and 3d6 per hit is simply pathetic. These are not mere bullets; they're CANNON shells. A elephant gun round can kill an elephant... which has 104 hp. These are orders of magnitude more powerful.