It does no good for you, since it's second-hand as posted here, but...
I have heard at least one (only 1? I furgit sometimes...) first-had report of reduced 296 loads failing to light up and leaving a bullet lodged midway down the bore.
Comparing the old Speer loading data with Winchester, the Win data appeared to be at teh 3% reduced level already. However, the fact that Win used different bullets (of the same weight) makes such suppositions dangerous.
Stick with the published load. If you want less flash, blast, and velocity, use something like Alliant's Power Pistol, which *can* be downloaded from max.