I've read that some bullets start to tumble at certain ranges. Does weight and b.c have anything to do with this? On a ballistic program, there isn't much difference between the two at a 1000yrds other than energy.
The bullets w/ the bad rap for tumbling and such are 168gr SMKs... which have a different angle to the boat tail as they were designed with 300m shooting in mind some 30-40 (or more) years ago. The 168gr VLD should be fine. I've never ran one that fast, but you should be good to go either way.