Named for the Greys River in Wyoming.
hook - Dai Riki 280 #10
underbody - non-tox .025 (optional)
rib - Danville Flymaster Plus black
thread - Danville 6/0 black
tail - goose biots natural
shellback - goose quill
abdomen/thorax - muskrat
hackle - hen black
Part 1
mash barb, wrap shank with non-tox; cover with thread, tie in rib
even tips on a pair of biots (convex opposed); measure (gap width past bend), tie in/trim butts, smooth with thread
prep/tie in goose quill
dub thread/dub abdomen to 2/3 mark