Dave,
I'm not so much a "believer" in trajectory numbers as I am interested in the comparison of those numbers between different loads. I always verify on the range what the load actually does and then go back and fine tune the chart to match actual results. This helps me form a mental picture of what the load is doing and guides me in both the setup of the gun and implimentation of theloadin the field. Of course being able to compare different loads is a nice benefit and helps spot BS when someone spouts about their super duper load that will drop such and such at some way out there distance, like the guns that claim 500 yard performance out of loads that have a 6" PBR ofmaybe 200 yards and are down4 to 8 feet at 500 yards. That throws up a red flag to me real quick.