Half of my ghost gun is complete...aero precision (blemeshed?) Upper receiver...ar-stoner 5.56, 16", 1 in 7 twist, SOCOM profile barrel, with carbine gas port. with ar-stoner M16 BCG. Yankee hill diamond series spectre length free float rail. Generic mil-spec parts kit and charging handle.
You can increase this bows power by using a larger pipe slipped snugly over the other pipe.... i built one like this when i was a kid and i was easily launching arrows over 100 yards... the draw weight was incredible.