Getting complete combustion of anything is difficult, just look at the PCV valves and catalytic converters on your car. One way to reduce residue and unburnt powder is to raise combustion temperatures. Titegroup does this, but the trade off is that the pistol gets hot and people using lead bullets report increased leading.
I dump my empty revolver cases from the cylinder right into a container, I always have lots of partially burnt powder in the can. So what, my loads shoot well.
And I also consider a misfire rate of one rounds in 60 is undesirable.
If I'm not shooting, I'm reloading.