Taken from Greg Porter's introduction to the hypertext version:
This is the digital version of the 3G3 weapon design system, also known as Guns! Guns! Guns!. The electronic edition differs from the original only in that we've added a little color, and some useful cross-referencing here and there. You won't be able to do much full-page reading of it unless you are fortunate enough to have a full page monitor, but you can print off the .pdf file to a laser or color printer and get a copy with the exact same information you would get in the printed version, for a significantly lower cost.