)The Booster Zero PPD rules can be found in this thread.
This is Mike West's proposed "new" ISC PPD rules, which has gotten rave reviews from everyone who has seen it (which includes me and Mike Filsinger, so far).
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The capsule version:
We can easily reduce the PPD to-hit determination to a
single die roll. The odds work out pretty closely.
The proposed procedure:
Use the existing to-hit numbers and the existing chart.
If the to-hit target (or less) is rolled, all pulses
hit (4 for normal loads; 6 for overloads). If the target
is missed, reduce the number of pulses by the amount
missed. (4A4) modifiers (if any) are simply added to the
rolled number.
Example 1:
So, for example, a PPD is fired at range 12. If an 8
(or less) is rolled, all four pulses hit. If a 9 is rolled,
three pulses hit. If a 10 is rolled, two pulses hit. If
an 11 is rolled, only one pulse hits. A 12 or more results
in a complete miss.
Example 2:
An overloaded PPD is fired at range 7 at an Orion. So, if
an 8 is rolled (which is modified to a 9 by the stealth),
then all six pulses hit. Anything less is the same. If a
9 is rolled (modified to 10), then only five pulses hit.
If a 12 is rolled (modified to a 13), then only a single
pulse hits.
The full explanation:
Working out the odds of rolling at or under a certain
number on 2d6 is (in part):
2-6: 42%
2-7: 58%
2-8: 72%
2-9: 83%
2-10: 92%
2-11: 97%
2-12: 100%
The odds of rolling 2-9 on a specific series of rolls:
Rolls 1 2 3 4 5 6
2-9 83% 97% 99+% 99+% 99+% 99+%
2-8 72% 92% 98% 99+% 99+% 99+%
2-7 58% 82% 92% 97% 99% 99+%
2-6 42% 66% 80% 88% 93% 96%
(This first column in the 2-8 roll shows the odds of
rolling a 2-8 given one chance. The second column shows
the odds of rolling a 2-8 given two chances. The third
column shows the odds of rolling 2-8 given three chances.
And so on.)
Expressing this in terms of a target number on 2d6:
Rolls 1 2 3 4 5 6
2-9 9 11 12 12 12 12
2-8 8 10 11 12 12 12
2-7 7 9 10 11 12 12
2-6 6 7/8 9 10 10 11
(This converts the first chart into the target number
on 2d6 that most closely represents the odds given in
the first chart. The only bad match is the target number
of the "2" column on the 2-6 range.)
From the above progressions we can see that things lay
out pretty nicely. There is a gap between the first and
second rolls, but besides that, things flow with a very
nice progression.
The result is that we can indeed use a single die roll
to determine the number of PPD hits a target receives.
To do this we simply use the target rolls we already have
and state that if you make the target roll, all pulses
hit (4 for normal loads; 6 for overloads). For each number
that you miss the target by, you lose a pulse.
The advantage of this is that it is simple, handes (4A4)
modifiers without problem, and reduces the to-hit roll to
a single roll.
The disadvantage is that it ignores that gap we see in the
second charge between the "1" and "2" columns. However,
this is not really changing the odds significantly, and
can be viewed as a slight balancing factor to compensate
for the other advantages the PPD gains in FC.
