MissileWorks. They sell them, and also have them as on option with the sleds for their altimeters, they also sell screw switches, which allow armin/disarming with a screwdriver in the vent hole.
You have to do a bit more work to find things, but they have just about every kind of switch that you could possibly want. Also stuff is much cheaper, they also ship USPS so you can get some pretty low shipping costs as well.
I use Switchcraft 4PDT - part number 50212LX (Mouser Part # 502-50212LX)
Just epoxy over tabs of the metal body where they bend over the phenolic....usually also epoxy over the soldered connections too at the same time for insulation & structural strength.
100's of flights in dozens of [team] rockets without a problem......
if you are not handy with a soldering iron, we also carry a version of the rotary switch with a terminal block mounted on the back. It does require more internal depth though.