Ok I'm feeling dumb right now. I got one of these momentary dpdt switches and can see via ohm meter that the middle terminals are normally connected to one of their corresponding edge terminals when the switch is "NOT pushed." However, when I push the switch, I see the connection broken on the terminal that was previously connected, but I also expect the middle terminals to be connected to the "other" set of edge terminals. However, I don't see continuity. IOW, I expect the dpdt functionality explained in this article, albeit a toggle dpdt. I want to hook this up as a "normally off" switch rather than a "normally on" switch. I do need a dpdt since I need it to control two circuits. I have used TWO different ohm meters just to make sure. What gives?
There is no guarantee it will be the center terminal that is common. Just probe it out. It will almost surely be symmetric on either side, but it may be one of the end terminals that is the common for each side.
In any case, there are only two 'states' for the switch, so write down what is connected to what when the plunger is pressed and what is connected to what when the plunger is released. If there are 6 connections you need to make a total of 30 continuity tests (5 + 4 + 3 + 2 + 1 for each state) to be completely systematic about it. If you short a few together and have a good guess you can cut it down to just a few tests.
Edit: Here is a similar looking part, and the middle indeed is the common: