
I came up with the question of how do the actual rules contemplate archers on horseback?
The rohirrim, for instance, can use Bow and nowhere is it said that a bow cannot be used from horseback.
I think there might be two different situations that can come up with mounted archers:
A) A mounted character or NPC that, simply, is in Rearward Stance firing a bow.
While the character would still get the Armour Encumbrance Reduction benefit of being mounted, I don't see any other benefit or hindrance applying to him. Enemies with ranged weapons might still target the mount to force Riding tests. But as far as I can see, the forced Riding test doesn't prevent the mounted character from attacking. That is, the Riding test is made in addition to his action (firing the bow, preparing shot,...), not instead.
B) A mounted character or NPC that wants to fire his bow AND stay out of melee range from his enemies. I think that was a common tactic by some eastern cultures. Or a company of mounted elven archers might look great like this.
That might be a little trickier, if supported by the RAW at all.
Maybe it should be considered as an attempt to chain Opening Volleys with Escape Combat (given that horses grant a bonus to the Athletics roll). So, it could look like this:
1.Opening Volleys are resolved
2. Proceed to Close Quarters
3. When it's the Mounted Archer's turn to act, he tries to Escape Combat
4. If succesful, the Mounted Archer decides to enter the Onset phase again next turn
5. Opening Volleys are resolved again
If the Mounted Archer is part of a group that includes melee fighters, he might simply be considered as in case A.
Any thought? As said in the beginning, I'm not trying to house-rule anything. Just to understand what does the RAW support, as I've had the experience of finding once and again that the RAW can be fully usable for situations not specified in the rules, but that seem to have been taken into consideration when designing the mechanics of the game.