TinMan

I'm not real sure I understand your Daffy-Nitions. You're "pushed forward" (from where??) and pushed back (from where??)

Normally, we start with Head Space. Nominal Head Space is considered to be .004 - .005, measured with cartridges (dummy) and measured between the recoil shield and cartridge head. Then we look at Barrel to Cylinder Gap and End Shake. There are varying opinions on Barrel to Cylinder Gap. However, End Shake should be held to .001 or .002 with the resulting Barrel to Cylinder gap of .004 or .005

People ARE Hazardous to Yer Health!!