In RTR 6.1, the Gaul Mercenary slingers with 2 chevrons of experience only did 4 missile damage and this would kill maybe 4 men per volley, this was against another gaul slinger unit. Well they did have some armor, the helmet and that small chest piece to protect the heart. I'd think that the shield would have to be more, but the defense skill sounds right.
What did you mean by leathality (0.1)?