One of the things
I’ve always liked about Unknown Armies is the amount of
information it derives from a single d% roll. The retention of funny
dice is my main complaint with the RuneQuest SRD family of
games (OpenQuest, Legend, Delta Green,
et cetera), especially since they usually only come up in very
specific circumstances—HP and Sanity loss. (I have the same problem
with 3eera games; conversely, S&W White Box’s focus on
only two die types is the main thing I like about it.)
Unknown Armies’
method of reading percentile rolls for damage results, however,
doesn’t translate directly into RuneQuest SRD games due to
Unknown Armies’ HP scale is also on a percentile scale (with
50 being the equivalent to RQ’s 10 HP).
The following is a
set of suggestions for reading a d% roll, such as an Combat Style
attack roll in RQ, to derive a damage result for a RQ scale of HP
(i.e. 318, with an average of 10). To use these damage code
suggestions, choose which of the damage codes you want to build a
damage scale from. Since codes these are awkward to note in weapon or
monster statlines, I suggest choosing a small subset of damage codes
(56) so that the players can memorize them. Then name or number each
damage code you’re using on the scale (for example: very light,
light, medium, heavy, very heavy) and then assign one to each
source of damage (weapons, hazards, whatever). You can either do this
ahead of time, or just key each damage code to a die type or range of
die types for onthefly conversion.
At some point I
might make this post or a variant of it available as a PDF product
(with OGC licensing). Please let me know in a comment if that’s
something you’d like to see.
[%] in the damage
codes indicates the percentile attack roll result. [%10] and [%1]
mean the digit on the die of the 10sdie and 1sdie respectively.
When considered as individual digits, a 0 on the [%10] die is a 0,
and a 0 on the [%1] die is a 10. For example, if the percentile roll
([%]) is 45, [%10] would indicate 4 and [%1] would indicate 5.
Notes: Because the
attack rolls are rolled under a skill %, any code will have a slight
scaling effect based on the attacker’s skill, as the range of
successful rolls will restrict possible results. For example, someone
with a skill of 50% will only have a [%10] damage die range of 0 to
5 in any successful roll (for an average die result of 2.5). This
makes estimating the lethality of various sources of damage slightly
more complicated.
Damage codes: 
½ [%10]

[%10] 
Lower of [%10] and [%1] 
½ [%1] 
[%1] 
Higher of [%10] and [%1] 
Sum of [%10] and [%1] 
Sum of [%10] and [%1] x2 
[%] 
These codes are slightly more complicated: 
[%10] minus [%1] 
[%1] minus [%10] 
Sum of the highest of [%10], [%1], and a third die. 
Sum of [%] and a third die. 
Average of [%10] and [%1] 