In reading RUNFIVERUN's reply,, I got to thinking about how powder burns. In an '06 case filled with slow burning powder, the burn starts at the back and pushes powder, bullet and all down the barrel. Raw powder is pushing the bullet well into the bore. All is well and good. The powder is burning at a progressive rate and the pretty tubular shape has been crushed into a solid (40-50,000 PSI).

Now take a small charge and put it into a straight case. The powder is only half way up the side of the case and the primer flash goes down and lights all of the surface at once and burns straight down quickly - more of a detonation. (There have been studies of having all of the powder at the rear as opposed to all at the front, but I have not heard of the results.) "Faster" powders were designed to burn in open cases and I expect might burn even slower under these conditions than their big brothers.

As for my fillers, I stick with something more substantial, like fine corn meal and enjoy the tortilla smell.

Potato John