C.W. Richter
AH legend
Tubby may be able to add to this but I believe they changed the bolt style (<20 lugs down to 2 between the 740 and 7400 and the bolt is integrated into the carrier in the 7400.) I'm certain one performs somewhat better than the other. I'm more familiar w/ the 760/7600s as the 40s aren't legal here for hunting, but I've helped a few old-timers out of literal Jams with both! I always admired the BAR in 300 WM!