I shot this Mohegan style sinew/backed hickory bow with heat treated belly last year in a 3 D event where it rained most of the day & really didn't notice any weight change or arrow trajectory I wonder if heat treated belly & 6 coats of poly helped , the only time I see weight increase is in the winter when it's real dry , the Turks seemed to use there sinew bows in some pretty adverse wheather I'm interested in the smoke conditioning too , wheather proofing sinew could be a whole new thread !