Just curious, was the elk moving left to right from your position? Never did find your shaft? How was the nock attach to the shaft?
Sounds to me like you may have been correct in the assumption that you hit something prior to the animal, causing the shaft to slightly turn and enter at a forward right angle and flipping the nock off in the opposite direction... just guessing tho...
Hate you didn't find it. I,m also guessing when I say that i think it will most likely recover.
