I occasionally get slapped by the trigger guard on factory stocks. Mine is a wrist mobility problem - too many years of riding bulls has left me with little ulnar deviation, so my fingers usually lose contact with straighter gripped stocks, and my index finger just hangs out in space. On video, it sure looks like my finger is the part flying into the back of the trigger guard, rather than the other way around. It’s just a matter of discipline for me to remember to keep my fingers in tight to the stock, instead of letting my hand float.

Or better still, my solution is indeed changing to stocks with better fitting grip angles so my fingers all find happy homes, snug against the stock.