You also have to understand how the game updates other players' positions for you on your computer. The way I understand it, to save on the amount of data your PC is receiving at any point in time, you get updates on another players' position continuously if they are near, but it takes much longer if they are far away from your present position.
Think of when you first move to a field under heavy attack from across the board. You do not instantly see all those players in the air. It takes a few seconds before their positions are updated relative to yours. That is, while you were at base 1, your PC was getting updates quickly from players nearby, but the players across the board at base 2 were only sending updates every few seconds. When you move across the board to base 2, it takes a few seconds for all that positional data and refresh time to catch up to your new position.
Player A is at base 1 and Player B is vulching base 2. Player A's PC sends player B's position, and it says "A is way over there at base 1, next positional update in 5 seconds" (making time up). At that moment, Player A moves to base 2 and ups a plane. Only after that 5 seconds does A send the update to B's PC, even though his position is now relatively near. This time, though, it says "wow, you're close, sending continuous updates now."
So, to have a better chance to cause a significant delay between your spawn and when the camper sees you, you just need to go to the farthest base you can and sit for a few seconds. Then, as quickly as you can, move to the previous base, up, and start turning your turret.
From your point of view, the spawn camper may not even appear to be there for a brief moment, but keep your turret turning anyway. Hopefully, by the time all the positional refreshes happen, you will have your turret turned around and be able to ping him before he perceives / kills you.