Factory rounds are highly variable. Hand loading is the only way to get reliability beyond 150 yards. Magnum is good, though. I like to load the 45 Colts real light so I can watch the lead bullet all the way to the backstop 400 yards downrange when I am shooting in daylight.
7.8gr unique behind 158gr GDHP is my comfortable load. if i really want screamers, 16.6gr of 296.