The thing is, if your brass isn't all matched up by volume you're still not going to eliminate extreme spreads. A very precise powder charge is never a bad thing but you'll never see a rifle's potential realized until the other variables are addressed. Using QuickLOAD, I've done a comparison using .308 Winchester in a 20-inch barrel length, a 168-grain A-Max, and a max (calculated) charge of H4895 which is 44.0 grains.
With case capacity set at the default value of 56 grains of water, velocity is 2690 fps @ 62158 psi.
Use a case capacity of 57 grains of water and velocity decreases to 2666 fps @ 59499 psi.
Now set case capacity back to 56 grains of water. It takes a powder charge variation of 0.4 grains to cause as much variation as a difference of 1 grain of water capacity.
If I had a choice between perfect brass and my junky old Chargemaster OR run-of-the-mill brass and perfect powder charges, I would take the perfect brass every time. Not that I think perfection in either area is possible...
I am not criticizing those who want as precise a powder charge as they can get and I'm not saying you're doing it wrong, but I AM saying that if your dotting the "I"s but not crossing the "T"s then you're missing out. Me---I don't worry about such minute details. I buy decent brass and charge them as carefully as my equipment allows and I am [mostly] satisfied---key word. I don't own a quarter-MOA rifle in the first place, but if I did I might very well pursue the last 1/10-MOA potential.
Sorry for the rambling...
