As a stocker, I see several questions to ask. Are the makers the same? In my career, I have found the differences in maker receiver sizes make a difference even when using the same dimensions from another gun mfg'er. Are the stocks set up the same with the same kind of hardware (solid butt, recoil plate, recoil pad). Are the rib types the same? How is the regulation of the barrels (use a laser pointer inside the bores to determine POI at 30 ft.)?
I have found 1/16" in comb height makes only marginal differences in the POI for most shooters ( there are exceptions to every theory). The 1/2" difference in Pitch may affect POI depending on your mounting process and your style of shooting. The 1/16" cast of the comb difference is telling, as your second gun patterns left. As Brian said...it needs more cast off.
