Wow! I never checked! And for a guy who has a GS-1 and a GS-3, as well as the "GS-2" with a modified tender, I just never noticed the driver size! I will check tomorrow, but meantime, what an excuse to again share my photos!
I will spare you the GS-4s - they are nice models, but for the most part factory built. The Max does have Overland drivers, but it would take an expert to tell it from USH.
I also had no idea the really excellent Weaver was basically the Williams - but it makes sense. Gimme a minute to find the photos . . .