[WhoKnowsWho]

Anyone know the reason behind the Sig's naming of their handguns?

[Siggyboy]

What do you mean by name, Sig, Sig-Sauer, P-220?

The company name SIG is short for "Schweizerische Industrie Gesellschaft" which means "Swiss Industry Corp" in English. It is a Swiss company. Back around 1970 Sig was having trouble exporting its firearms out of Switzerland and entered into a deal with the old German firearms manufacturer J.P. Sauer und Sohn to form SIG-Sauer. Both companies were not too far from each other geographically. The first SIG pistol was the P-210 developped from a French prototype for the Swiss military in the 1940's, though SIG goes back way before then (making other products). The first SIG-Sauer pistol was the P-220 made at the modern factory in Germany beginning in 1974. Of course, the P- in the name of all their classic pistols stands for "Pistole".

[WhoKnowsWho]

Sorry, all Sig-Sauer pistols... ie. why do they go 210 to 220 to 225 etc... I figured it is something not as cut and dried as the Glock naming conventions.

[B27]

The numbering is basically consecutive but there are some exceptions to this. The gaps in numbering are often the result of prototypes that never made it into production.
Chris may well have something about it on his site http://home.t-online.de/home/clswimm/sig/sig.htm