It might be helpful to look at other shotgun makes to determine what constitutes a different frame size. For example, are all no.2 frame Paker frames identical, or are there significant dimensional differences among no. 2's? And where do we find the differences between a no.2 frame, and a no. 1 1/2 or a no.3 frame, besides the obvious breech widths with different gauges or different weight barrels?
Not 100% sure, but I seem to recall that Parker Gun Co. utilized different sized frame forgings. That would make sense from a standpoint of minimizing grinding and filing to final size. We don't know if Lefever did the same, or if they just made a bigger pile of metal chips when they built their smallest lightest guns.
