The whole capturing and recapturing artillery lark throws up some questions with the rules that really need looking at.
1.
Capture seems fairly clear:
When any base of an unlimbered enemy battle group is contacted in a way that would normally result in close combat the whole artillery battle group is captured unless all contacted bases have rear support. P126
2.
Recapture is not so clear, but occurs when:
A battle group belonging to the previous owner, and already in contact, routs (all) the capturing enemy battle group(s). P127 bp1
[or]
A battle group belonging to the previous owner moves into contact (in a way that would normally result in close combat) with an artillery base that does not have rear support from the current owner's troops. P127, bp2
Para 1 doesn't seem to be a major problem, but consider what happens if the LH that captured the artillery is routed two moves later when it is 18 m.u.s away.
Para 2 is even more difficult. Moving into contact "in a way that would normally result in close combat" is usually interpreted as a charge in the impact phase, but:
To be allowed to declare a charge, there must be an enemy base that can be "legally" contacted. P72, my emphasis
AND
Uncontrollled artillery does not count as enemy to either side. P127, last sentence of penultimate paragraph
Which means it is not possible to charge an uncontrolled artillery bg because it isn't an "enemy."
So, can you recapture it in the Manoeuvre phase by just walking into it? Probably not, because the only movements in the phase that can "normally result in close combat" are into overlap, sideways shifts and turns (see pages 102 and 103). All of which would be difficult to apply in this case.
I think we should view uncontrolled artillery as having a similar status to an unfortified camp for this purpose - it can be captured/recaptured by any movement in the Manoeuvre phase that makes/maintains contact, as well as by pursuits and charges declared on other battle groups.
3.
Interpenetration of uncontrolled artillery
It is extremely frustrating and more than slightly illogical/unrealistic that uncontrolled artillery represents a barrier to movement of both sides. As already pointed out in this thread, the artillery is more like a linear obstacle than a solid block:
Artillery base depths vastly over-represent their actual historical depth. Hence a battle group in a position to give rear support is treated for all purposes as if its front edge was the front edge of the artillery... P126, bp1
The front edge of FF is treated as the front edge of a battle group defending them... P157, bp1
Undefended field fortifications do not impede the movement of troops... P 157. final bp
A [linear} obstacle is otherwise treated as if it was a field fortification. P170, final sentence of definition of obstacle.
In my view, uncontrolled artillery should be treated by analogy with linear obstacles for movement, but not for being defended.
This would mean that troops of the side which currently "owns" the artillery simply move through it as if it wasn't there, being allowed to charge targets beyond it if they can.
Would this be an interpenetration or not?
My view is not, as the interpenetration rule concerns moving
through friendly troops... P 67, para 1, my emphasis
Since artillery become uncontrolled when their crews are killed, captured or chased away, all that is left are bits of wood and metal which do not fit any reasonable definition of "troops." Nor can they be "friendly."
Also, this would allow the non-"owning" player to charge through the artillery thereby recapturing them because this would be movement "that would normally result in close combat."
Whether this can be addressed in the FAQs or needs an errata, I don't know.
Dave