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Is a fully mounted Rohan army still hit with the bow limit?
Yes. Although it shows all Riders of Rohan come equipped with a bow, Games Workshop suggested that you play as only 1/3 of them having bows. I'm sure them all being equipped with bows was just a carry over from the older editions that never got remedied.
Yes, only those firing count as bow-armed. On the others its purely decorative.
http://www.armyroster.com Check out my ToP WIP in the projects section!