Missile Weapons in Combat

In general, missile combat is handled identically to standard melee. Intentions are announced, initiative is rolled, and attack rolls are made. However, there are some special rules and situations that apply only to missile combat.
Missile weapons are divided into two general categories. The first includes all standard, direct-fire, single-target missiles — slings, arrows, quarrels, spears, throwing axes, and the like.
The second category includes all grenade-like missiles that have an area effect, no matter how small. Thus an attack with these weapons does not have to hit its target directly to have a chance of affecting it. Included in this group are small flasks of oil, acid, poison, holy water, potions, and boulders. Hurled boulders are included because they bounce and bound along after they hit, leaving a swath of destruction.

Range

The first step in making a missile attack is to find the range from the attacker to the target. This is measured in yards from one point to the other. This distance is compared to the range categories for the weapon used. If the distance is greater than the long range given, the target is out of range; if the distance is between the long- and medium-range numbers, the target is at long range; when between the medium- and short-range medium range is used; when equal to or less than the short-range distance, the target is at short range.
Short-range attacks suffer no range modifier. Medium-range attacks suffer a -2 penalty to the attack roll. Long-range attacks suffer a -5 penalty. Some weapons have no short range since they must arc a certain distance before reaching their target. These attacks are always made with an attack roll penalty.

Rate of Fire

Bows, crossbows, and many other missile weapons have different rates of fire (ROF) — the number of missiles they can shoot in a single round.
Small, light weapons can be thrown very quickly, so up to three darts can be thrown in a single round. Arrows can be nocked and let loose almost as quickly, so up to two shots can be fired in a single round. Some weapons (such as heavy crossbows) take a long time to load and can be fired only every other round.
Whatever the ROF multiple missile shots are handled the same way as other multiple attacks for the purposes of determining initiative. The ROF of each missile weapon is listed in table 45.

Ability Modifiers in Missile Combat

Attack roll and damage modifiers for Strength are always used when an attack is made with a hurled weapon. Here the power of the character's arm is a significant factor in the effectiveness of the attack.
When using a bow, the attack roll and damage Strength modifiers apply only if the character has a properly prepared bow. Characters never receive Strength bonuses when using crossbows or similar mechanical devices.
Dexterity modifiers to the attack roll are applied when making a missile attack with a hand-held weapon. Thus, a character adds his Dexterity modifier when using a bow, crossbow, or axe but not when firing a trebuchet or other siege engine.

Firing into a Melee

Missile weapons are intended mainly as long-range weapons. Ideally, they are used before the opponents reach your line. However, ideal situations are all too rare, and characters often discover that the only effective way to attack is to shoot arrows (or whatever) at an enemy already in melee combat with their companions. While possible, and certainly allowed, this is a risky proposition.
When missiles are fired into a melee, the DM counts the number of figures in the immediate area of the intended target. Each Medium figure counts as 1, Small (S) figures count as 1/2, Large as 2, Huge as 4, and Gargantuan as 6. The total value is compared to the value of each character or creature in the target melee. Using this ratio, the DM rolls a die to determine who (or what) will the target of the shot.
For example, Tarus Bloodheart (man-size, or 1 point) and Rath (also man-size, or 1 point) are fighting a giant (Size G, 6 points) while Thule fires a long bow at the giant. The total value of all possible targets is 8 (6+1+1). There's a 1 in 8 chance that Rath is the target; a 1 in 8 chance that Tarus is hit; and a 6 in 8 chance the shot hits the giant.
The DM could roll an 8-sided die to determine who gets hit, or he could reduce the ratios to a percentage (75% chance the giant is hit, etc.) and roll percentile dice.

Taking Cover Against Missile Fire

One of the best ways to avoid being hit and injured is to hide behind something — a wall, a tree, a building corner, a heap of boulders, or whatever happens to be available. Professional adventurers, wishing to make this sound heroic, call this taking cover.
Taking cover doesn't work particularly well in a melee, since the cover hampers defender and attacker equally. However, it is quite an effective tactic against missile fire.
There are two types of protection a character can have. The first is concealment, also called soft cover. A character hiding behind a clump of bushes is concealed. He can be seen, but only with difficulty, and it's no easy task to determine exactly where he is. The bushes cannot stop an arrow, but they do make it less likely that the character is hit. Other types of concealment include curtains, tapestries, smoke, fog, and brambles.
The other type of protection is cover, sometimes called, more precisely, hard cover. It is, as its name implies, something a character can hide behind that will block a missile. Hard cover includes stone walls, the corner of a building, tables, doors, earthen embankments, tree trunks, and magical walls of force.
Cover helps a potential target by giving the attacker a negative modifier to his attack roll. The exact modifier for concealment or cover depends on the degree to which it is being used as shelter. A character who stands behind a two-foot wall is a pretty obvious target, especially when compared to the character who lies down behind that wall and carefully peers over it. Table 59 lists the different modifiers for varying degrees of cover and concealment.

Cover also has an effect on saving throws, granting the character the modifier listed on Table 59 as a bonus to his saving throws against spells that physical damage (e.g., Fireball, Lightning Bolt, etc.). Furthermore, a character who has 90% cover (or more) suffers one-half normal damage on a failed save and no damage at all if a saving throw is successful. This assumes, of course, that the fireball, lightning bolt, or whatever, hit the cover—a man crouching behind a stone wall would be protected if a fireball exploded in front of the wall, but would not be protected by cover if the blast occurred behind him, on his side of the wall.

Grenade-Like Missiles

Unlike standard missiles, which target a specific creature, a grenade-like missile is aimed at a point, whether this point is a creature or a spot on the ground. When the attack is announced, the player indicates where he wants the missile to land. This then becomes the target point and is used to determine the direction and distance of any scatter.
Most grenade-like missiles are items of opportunity or necessity — flasks of oil, vials of holy water, or beakers of acid, for example. As such, items are not listed on the equipment tables for range, ROF, and damage. The range each can be thrown varies with the Strength of the character and the wetght of the object.
A missile of five pounds or less can be thrown about 30 feet. Short range is 10 feet (0 - 10), medium range is 20 feet (11 - 20), and everything beyond is maximum range (21 - 30). Heavier items have reduced ranges. Just how far an object can be thrown is decided by the DM.
Exceptionally heavy items can be thrown only if the character rolls a successful bend bars/lift gates check. In no case can a character throw an item heavier than his Strength would allow him to lift. Thus, the DM can rule that a character would have little trouble chucking a half-empty backpack across a ten-foot chasm, but the character would need to make a check in order to heave an orc ten feet through the air into the faces of his orcish friends.
Once a container hits, it normally breaks immediately. However, this is not always true. Some missiles, like soft leather flasks or hard pottery, are particularly resistant. If there's some doubt about whether or not a thrown object will break, the DM can require an item saving throw to see if it shatters or rips, spewing its contents.
If a missile is off-target it is important to know it landed — an errant grenade-like missile could present a hazard to other characters, start a fire, or eat a hole in the floor. The process of finding where it lands is known as scatter. First roll 1d10 and consult the Scatter Diagram.

Next determine how far off the mark the throw is. If the throw is at short range, use a 6-sided die. If the range is medium, a 10-sided die. If thrown to long range, roll 2d10. The number rolled is the number of feet away from the intended target the missile lands.
The damage taken from a grenade-like attacks depends on whether a direct hit was scored or the target was in the splash area. The grenade-like missile effects table lists the area of effect for a direct hit and damages from direct and splash hits.
The Area of Effect is the amount of space covered by a direct hit. Any creature in the area of effect will take damage according to the Direct Hit column. All creatures within 3' of the area of effect are subject to splash damage.

Types of Grenade-Like Missiles

Acid damage is particularly grim. Aside from the possibility of scarring (which is left to the 0M). acid damage cannot be healed by regeneration. It must be healed normally. Thus it is very useful against regenerating creatures such as trolls. Acid is very rare.
Holy water affects most forms of undead and creatures from the lower planes. It has no effect against a creature in gaseous form or without material form.
Unholy water (essentially holy water used by evil priests) affects paladins, creature whose purpose is to defend good (lammasu, shedu, etc.), and creatures and beings from the upper planes.
Holy (or unholy) water affects creatures as does acid, causing damage that cannot be regenerated but must be healed normally.
Oil causes damage only when it is lit. This normally requires a two-step process — first soaking the target in flammable oil and then setting it afire. Thus using flaming oil often requires two successful attacks. A direct hit from flaming oil burns for two rounds. causing 2d6 points of damage in first round and 1d6 points in the second round.
Poison is generally not very effective as a missile weapon. Most poisons take effect only if the missile scores a direct hit, and even then only if it drops into the gaping maw of some huge creature. Contact poisons have normal poison effects on a direct hit.

Boulders as Missile Weapons

Hurled boulders are handled using the grenade-like missiles rules, even though they do not burst. Boulders tend to bounce beyond their initial point of impact and can hit several characters in a single attack. They are particularly devastating against tightly packed groups.
When attacking with a boulder, determine the target, to-hit number, and scatter (in case of a miss) according to the rules for grenade-like missiles. The distance the boulder scatters should be doubled, however.
If the boulder scatters to the left or right, it moves roughly 45 to 60 degrees off the original line of attack. A boulder moves along this line for 3d10 feet. If the targets are in a relatively open area (a group marching through a snow field, for example), there is only a slim chance that anyone will be hit by the bounding missile.
If the boulder moves through a space occupied by a character (or monster), roll again for a hit (recalculating THACO as necessary), applying a -2 penalty for each 10 feet, or fraction thereof, the boulder has bounced since it hit.
If the characters are in an area where movement is restricted (a formation of pikemen, for example, or a party in a 10' wide corridor). no additional boulder attack roll is made. The boulder strikes all targets in its path.
The damage done by a boulder as a result of scatter is less than from a direct hit. Roll the damage normally, but subtract the distance in feet the boulder has bounced to that point. This is the damage inflicted on the target.