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The Kroot Knarloc Riders in the Imperial Armour Update 2004 have a couple of different attacks, two for the Knarloc itself and one for the rider.
The rider is armed with a kroot-rifle (2-handed weapon on a mount ???) wich gives an additional attack as if the model has an additional hand weapon.
Does this also work for kroot riding knarlocs ?
And when the model charges, does the knarloc and the rider both get an extra attack ? If not wich one get the extra attack (they both have different strength-values).
Hmm, good questions. I can only partly answer, and I'm not too sure of the validity of it.
In the Imp Guard Codex, Rough Riders get an extra attack if double armed because the horse steers itself, unlike a bike which needs at least one hand to control. I would say the same for the Knarloc rider applies.