Cannons, Mortars, and Chainguns

While by no means common, below is a following description of crew-serviced weapons known to be in use by military and well-equipped mercenary companies. In general, acquisition and upkeep of such devices goes beyond the means of simple adventurers, both due to the high cost of upkeep and the sheer load required for effective deployment. Unlike other black powder weapons, weapons of this caliber use the Craft(Heavy Arms) skill when crafting, cleaning, and reloading. Unless otherwise noted, these weapons may not be upgraded.

Chain Gun — This semi-portable weapon emplacement is designed to be operated by two or more combatants. The weapon itself, comprised of the gun, a heavy tripod, and ammo stores, take up its own 5 ft square. Setting up a chain gun requires a full round, but once placed operation is relatively smooth. The sheer bulk of the weapon, often combined with blast plates mounted on either sides of the rotating multi-barrel assembly, provide the gunner with a +4 cover bonus to AC. The primary operator may make a full attack as normal using the chain gun, but also has the option to make a strafing attack (see below). Switching operators is a move action, and the chain gun may only be operated once per round. The ammunition belt for which the weapon is known holds 14 rounds. This specialized piece of equipment is essentially a strip of thick leather, reinforced at precise intervals with bronze casing. Each casing must be hand loaded with powder and bullet, and thoroughly cleaned afterward to facilitate smooth firing. Removing an empty belt and seating the next chain requires two move actions, which may be made by separate operators. Despite this efficiency, the chain gun cannot be reloaded and fired in the same round.

  • Strafing — When making a full attack, the operator may choose to initiate a strafing attack in lieu of their normal iterative attacks. When strafing, the operator designates an initial target and may include all creatures in squares adjacent to that target to which the operator has line of sight. The operator may then make a number of attacks up to half the remaining rounds in the belt (max 7 for a full belt), so long as that number does not exceed their Base Attack Bonus. The gunner makes an attack against each target using their highest bonus, with a cumulative -2 penalty for the total number of attacks beyond the first. Each attack uses 2 bullets, but still deals 2d8 damage per hit. For example, strafing with a full belt and BAB +7 or higher empties the belt, and all 7 attacks are made with a -12 penalty.
Weapon Damage Damage (S) Critical Range Type Weight Price Ammo Reload
Chain Gun 2d8 - - x3 100 ft Piercing 200 lbs 10,000+ 150+ gp (belt), 10-12 gp DC 12, standard x2

Portable Cannon — While not as versatile as a light artillery piece, the portable cannon allows for greater portability and rate of fire, albeit at greater expense. This weapon fires 5 inch diameter cannonballs specially loaded into brass sabot packets. The prevailing model of modern portable cannon uses a forged clockwerk firing mechanism with a first-generation sliding breech load. When the cannon fires, the recoil forces the breech open and a specially designed mechanism ejects the empty sabot. This system allows reloading to happen rapidly, with gunners only having to be aware of the piping hot brass sabot shells flying out of the cannon. However convenient, this new design has proven somewhat unreliable for sustained combat. After firing three rounds the cannon’s barrel accrues enough fouling and debris to require intensive cleaning. If the weapon is not properly maintained it will accrue a cumulative 10% chance of total failure for every shot. Failure results in the cannon exploding, dealing 4d8 damage to all creatures within 10 feet (Ref DC 20 for half damage), ruining the cannon beyond repair.

Weapon Damage Damage (S) Critical Range Type Weight Price Ammo Reload
Portable Cannon 4d8 - - x3 200 ft Piercing 90 lbs 2500 gp 250 gp DC 10, standard

Portable Light Artillery — These fearsome cannons were originally designed to be wheeled, but greater numbers of these weapons have been converted to ’dyne use, or more disturbingly, found with simple slings attached. The particulars of design vary widely by manufacture: some versions have breech-loading chambers while others remain muzzle-loading; handles for aiming, crude iron sights, and other means of improving accuracy; lit-fuse powder chambers, and even spring-assisted percussion pins. Most designs allow for three kinds of ammunition:

  • Solid slug ammo is the preferred shot for heavily armored targets. Due to its sheer mass, a slug that hits its target has the capacity to continue through, endangering further opponents. If the initial attack hits, the shot may continue in a line to a secondary target within 10 feet, who receives a +10 bonus to AC. If this second attack hits, the second target takes 2d10 damage. If the second attack hits, the shot may continue once more in a line to a third target within 10 feet pf the second target. The third target receives a +20 bonus to AC. If the third attack hits, the target takes 1d10 damage. Specialized anti-armordyne slugs are available, albeit at high cost. These slugs ignore an armordyne’s damage reduction and are 200 gp per shot.
  • Explosive shells deal splash damage in a 10 ft radius in addition to damaging the primary target. A direct hit deals the listed damage (no save) and all creatures in the splash radius take 2d10 damage, half of which is piercing, half fire. A Reflex save DC 16 halves the damage in the splash radius.
  • Cannister shot is generally the last resort of any artillery piece. These shells are filled with small steel balls, designed to rip through advancing infantry forces. Cannister shot affects all creatures within a 60 ft cone. This is not a range increment; beyond 60ft the pellets from the cannon are too scattered and have lost too much speed to deal any damage. All targets within the cone must make Reflex saves against 1d20 + Gunner’s BAB; those who succeed take no damage. Those who fail take 4d10 piercing damage each.
Weapon Damage Damage (S) Critical Range Type Weight Price Ammo Reload
Portable Light Artillery 200 lbs 1500 gp DC 14, full round x2
—Solid Slug 3d10 - - 19-20/x3 140 ft Bludgeoning 6 lb per shot 30 gp
—Explosive Shell 4d10* - - 19-20/x3 140 ft Piercing & Fire 5 lb per shot 90 gp
—Cannister 4d10* - - N/A 60 ft Cone Piercing 4 lb per shot 50 gp

‘Martindale Chain-Fed Repeating Suppressor’ [Martindale Gun]?


As with all long-range warfare, incremental weather, new technology, and the chaos of battle often interfere with pinpoint accuracy. Some weapons may, at the GM’s discretion, be classified as “Deviating Weapons”. When attacking with a deviating weapon, the attacker may choose either to attack a specific target or a specific grid intersection. If attacking a creature, resolve the attack normally; if attacking a grid intersection, resolve the attack against AC 5. You cannot attack a grid intersection that is occupied (such as by a Large creature). Success indicates that the weapon functioned normally and accurately. In the event of a miss, the shot deviates. The shooter then rolls a d8. A result of 1 results in the shot overshooting the intended target in a straight line from the shooter. Rolls of 2-8 move the impact point in a clockwise direction one square per number. The shot also spreads away from the target a number of squares equal to the range increment. For example, Candor Bragg fires a portable cannon at an oncoming armordyne 550 ft away and misses. Candor rolls a 6 on the d8, resulting in his cannonball landing short and to Candor’s left. 550 ft is two range increments away, so the cannonball impacts three squares diagonally away from the ’dyne.

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Cannons, Mortars, and Chainguns

To Fly on Metal Wings EJacobRiley