How much weight can a character throw in a ranged attack?

Question

I have been wondering for the longest time now, how much weight is your limit when throwing objects. If you throw a weapon that you are not proficient with you get a -4 penalty, same is said about when you throw an object. But what I am wondering, is even with the penalty, how much weight can you throw based on your strength? and what penalty will you take?

Answer 1

The Dragon #295 Wizards Workshop column "Sage Advice" includes this exchange:

How far can someone throw something that is not a weapon? How much damage would a hit with such an object deal?

Here's an informal system the Sage worked up for throwing things. It's offered to readers of "Sage Advice" for commentary and playtesting.

You can throw an item that weighs up to one third your light load rating as an improvised thrown weapon.… You can throw the item with one hand, provided it is no larger or heavier than that would would be a one-handed weapon for you.… Anything bigger than what would be a one-handed weapon for you must be thrown with two hands and the throw requires a full-round action.

If you want to throw an object that's heavier than one third your light load, you cannot use it as a weapon. Instead, you make a Strength check to lob it near your target in the hopes of doing some damage. The result of the check determines the distance you throw the object, according to the guidelines below. If the item does not exceed your light load rating, triple the distance you can throw it as figured by the guidelines below. If the item exceeds your light load rating but does not exceed you medium load rating, double the distance as figured by the guidelines below.

• For a running throw (at least 10 feet of movement toward your target), you throw the item 5 feet +1 foot per point your Strength check exceeds 10.
• For a standing throw, you can throw the item 5 feet +1 foot per 2 points your Strength check exceeds 10.

If the item exceeds your maximum load rating but is not heavier than what you can lift, 5 feet is the maximum distance you can throw the item (but see below); you can't throw what you can't lift. For these heavy objects, don't bother with an attack roll. Just have the thrower pick a spot for the object to land.

If the Strength check result is too low to reach the target spot, the DM should pick one [a spot] that's on a straight line between the thrower and the target spot. All such heavy objects require two hands to throw and thus throwing them is a full-round action.

In all cases use the deviation diagrams… to see where the item really lands (assume a range increment of 10 feet). It's possible that the deviation roll will make the item travel slightly father [sic] than the Strength roll indicates. If the throw was only 5 feet, do not roll for deviation.

A creature in the object's landing spot gets a Reflex saving save (DC 15 + the thrower's Strength modifier) to avoid the object.

Damage from an improvised thrown weapon or a larger thrown item is equal to the thrower's unarmed strike damage or 1d6 points per 200 pounds of weight.… (110, 112)

The column is unsigned. This exchange predates the 3.5 revision, but, so far as I am aware, was never followed up nor later modified, making its status technically unofficial but, at least, interesting. Absent other guidelines, it seems a decent enough scaffold to build from, although, like most of 3.5, these rules tend to break down at the extreme edges.

Also see improvised weapons (referenced in the exchange above), the feat Fling Ally (Races of Stone 139-40) et al., and the prestige classes hulking hurler (Complete Warrior 40-2).

Answer 2

When you use an object that is not a weapon to make an attack, you have to use rules for improvised weapons. And penalty for using heavier weapons is not a function of weight, but the size category of the weapon.

So, what you need to do to determine whether the object can be thrown and what penalties should be used?

1. Determine which weapon the object resembles.

To determine the size category and appropriate damage for an improvised weapon, compare its relative size and damage potential to the weapon list to find a reasonable match. An improvised weapon scores a threat on a natural roll of 20 and deals double damage on a critical hit. An improvised thrown weapon has a range increment of 10 feet.

Note that you need not only to determine the weapon’s type but also its size category. Thus, a small tree trunk can be a huge club. And remember that weapon category is not a measure of its size but the size of the intended wielder.

A weapon’s size category isn’t the same as its size as an object. Instead, a weapon’s size category is keyed to the size of the intended wielder.

2. Find out whether the object is small enough to be used by the character.

The measure of how much effort it takes to use a weapon (whether the weapon is designated as a light, one-handed, or two-handed weapon for a particular wielder) is altered by one step for each size category of difference between the wielder’s size and the size of the creature for which the weapon was designed. If a weapon’s designation would be changed to something other than light, one-handed, or two-handed by this alteration, the creature can’t wield the weapon at all.

Thus, a trunk from the previous example is two-handed for a large creature and can't be used by smaller ones.

Note that throwing a two-handed weapon is a full-round action.

Throwing a light or one-handed weapon is a standard action, while throwing a two-handed weapon is a full-round action.

2. Determine the penalty.

Improvised Weapons Sometimes objects not crafted to be weapons nonetheless see use in combat. Because such objects are not designed for this use, any creature that uses one in combat is considered to be nonproficient with it and takes a -4 penalty on attack rolls made with that object.

A creature can’t make optimum use of a weapon that isn’t properly sized for it. A cumulative -2 penalty applies on attack rolls for each size category of difference between the size of its intended wielder and the size of its actual wielder.

So a large creature can throw the trunk from our example with a -6 penalty (-4 for improvised weapon and -2 for one size category difference) and have to use a full-round action to do so (a club is one-handed and becomes two-handed for a creature one category smaller).

(quotes from this page, emphasis mine)