I sent this to Warlord games and got an official response, its a shame that they dint add it to the FAQ but I will bug them to do that. Didn't want to offend anyone so I have redacted certain bits below. Warlord ticket ID #208427

I'm not trying to start a war, its just a game after all. Just wanting to get to the bottom of how the rule is meant to work.

Hi Warlord, something came up in a game last night re, cavalry:

Rules say:
"A cavalry unit can dismount as part of any Advance move. Once dismounted, riders move and fight as infantry. Troops cannot remount once dismounted."

But it doesn't define what the dismounted is i.e. how far can they move as part of that dismount.

I assumed it was (could be) 6" from the horses that the infantry can move and then shoot because I got my butt kicked by cav multiple times in tournaments by multiple people moving the horse 9" then dismounting 6" and then shooting. [Redacted]. However when I tried to use last night the guys objected arguing that it doesn't specify in the rules and also its not like a vehicle/transport because there aren't two order dice one for the horses and one for men.

I looked for Cav stuff in the FAQ
Compared the wording to version 2 which I think is identical
looked at the V2 FAQ
searched every instance of the words cavalry and dismount in both PDF rulebooks

…and couldn't really find it defined specifically. It just says dismount.

The only other place it uses dismount (apart from bikes, motorbikes and cav which I assume are all the same) is vehicles so I assumed dismount means the same as its talked about and defined in detail in vehicles (which allows either a run or advance by the way). But again, my opponent proposes that its different because its not 2 order dice just one.

Can you give me a ruling please I'm stuck on this army building wise [Redacted]

[Redacted banter about wargaming in general]

To which warlord responded as below:

I went back for another go (perhaps because i am an IT guy and wee need ALL our ducks in a row) see below:

 No problem, REALLY appreciate the help.

OK good to know.

One clarification, might as well get to the final exact ruling, we know that they can't dismount as part of a run (18" for a horse) it can only be an advance.

I did assume that by saying "… as part of any advance move" the rules meant to allow either (at the players discretion):

1. the horse to advances 9" (perhaps including firing because it's an advance move?) then the guys to "get off" where they are (they just get off and replace the horses in the exact same position)

or

2. the guys to "get off" where they start the turn (…they just get off and replace the horses in the exact same position) the guys can then do their advance 6" and then fire

However you have indicated below that to do a dismount, the horse is unable to move (just the man) so just option 2 above and the word 'any' is a bit of a red hearing? I'm I understanding that correctly?

...Warlords final response: