I thought this one was going to be easy to answer, but I can't find a good ruling on it.

Check out page 31 in the rulebook. This page gives rules for using artillery units to make a ranged combat formation, and gives the exceptions to the normal ranged combat formation rules.

A normal ranged combat formation may only target one opposing unit. There is nothing on page 31 that states that artillery formations may attack more than one marker . . . but nothing to say they cannot either.

Which do you think it is? Only one artillery marker for the formation? Or as many markers as there are targets on the primary attacker?

The formation rules state the specific ways in which the formation rules override the normal rules. There's nothing specifically listed in the formation rules that overrides the 'Multiple ranged combat attacks' rule. The core of the artillery rules refer to the 'artillery marker' in the singular, as do the formation rules. So I don't think it can be said that just the fact that 'artillery marker' is referred to in the singular in the formation rules overrides the 'Multiple ranged combat attacks' rule.

The real question is: Why would you do that?!

Just so you know artillery units can only make ranged combat formations with other artillery units so it can be done im sure you already knew that. I am pretty sure you would only get the bonus for firing at one token Id have to read the rulebook again to refresh my memory though.

Wow, it's been a long time since I've thought about this thread.

I never responded to eMouse's post from a year ago, but he was wrong on one point: the formation rules DO override the multiple ranged combat target rules. A formation attack may only be made against a single target.