The jumpholes lead to two /different/ Unknown system, by the way. The one in Alpha is only populated by a ton of Nomads. The one in Gamma has the traditional ton of Nomad ships, as well as two "easter egg" planets which are basically useless.
To get the weapons, just kill Nomads.....lots of Nomads. I've had times where it took around an hour to get a single weapon, and I've had times where I got 3 weapons in a row, so it's really random when they drop.