Yes it is the one in the upper right.
The apocalyptic barrage template works like this:
It is constructed of five overlapping 5" templates. These are each denoted separately, and marked with numerals one through six.
The four around the outside are marked one, two, three, and four, while the one in the center is marked five and six.
When you fire a weapon using the Apocalyptic Barrage template, you simply place the template, oriented however you want it to be oriented, over a model in the target unit (that model has to be in range of the gun). The template doesn't scatter, in the traditional sense. Roll one die for each 'shot' the weapon takes. In most weapons the number of dice you roll is denoted by a numeral in parentheses after the phrase "Apocalyptic Barrage."
Anyway, you roll the dice, and each die produces a hit against every model touched by the corresponding circle on the template--you don't roll for partials, you just hit them.
What is being suggested is that the Whirlwinds combine their fire into an Apocalyptic Barrage (x) where x is the number of Whirlwinds combining their fire. It doesn't make each individual shot bigger--they're still each five inches--it just makes their 'scatter', as I said, more predictable, and allows them to automatically turn partials into hits.
In point of fact, it doesn't increase the area of models affected by nearly the amount that the Vindicator Linebreaker Squadron does. It doesn't actually increase the area at all, only makes the area on the circumference of each shot better (by turning partials into fulls) whereas the Linebreaker squadron increases its area affected from 58.88 square inches (from three five inch templates) to 78.5 square inches (approximately) from one ten inch template.
Edited by Cale, 19 November 2007 - 10:45 PM.
Crusading against people who think they can just ignore the portions of the rules they don't like since before I even read R.O.V's signature!