Gary--Thanks. 15-oz isn't too bad. Dry, straight-grained spruce might be a good material for one. And instead of metal bushings, to save weight, the bored holes could be either sleeved w/ thin-wall fiberglass tubing or just treated w/ penetrating epoxy, to keep them from loosening up prematurely.

"There's more to optics than meets the eye."--anon

"...most of us would be better off losing half a pound around the waist than half a pound on our rifle."--dhg