I'm interested in the entire Model 100 series (all looking like Model 70 guns). Why was it created?

The Model 100 series pistols are basically Model 70 pistols - renamed. This was done in response to the importation laws enacted with the 1968 Gun Control Act. The Model 100 pistols are Model 70's that had barrel and grip frame lengths sufficient to allow importation into the USA. The 100 designation only lasted a short time before the Model 70 number was restored to the line, although the longer barrel and grip size were retained. There are 3 versions in the 100 line - The M100 was the (Model 70), the M101 was the (Model 71) and the M102 was the (Model 76).