Can you believe this guy?! Sheesh... noobs, amiright?!
What I was referring to is a ladder test, where you shoot one round at each charge, aiming at the same point. What happens, is more powder equals faster bullet speed equals higher up on the target, effectively climbing a ladder. If you do it correctly, you'll notice a few rounds cluster together vertically closer than the others, that is effectively a "node" and where your rifle will be most accurate, because the muzzle will be at the top (or stopped) of a node in a sine wave pattern from the harmonics of the barrel. Everything I read about this said start at 200yds and work out 100yds each iteration.
The longer distance you shoot, the longer the ladder will be which presumably means the nodes will be easier to spot.