can't find them (spoilers)

I hope it's ok if I start a new thread for this. I have searched and searched and can't find a clear answer.

Where is the blue gun?

If it's in the Wasteland, can someone help me with a specific place to look? I am pretty sure I have explored it all (except for past the blue barrier!) I found the Racetrack to the north and the Factory to the south. If it's not in the Wasteland, just "not in Wasteland" will be very helpful. I have also explored the Volcano.

thanks!

You need to defeat the

Spoiler

Skull Tank

in the area where you can't get past with Ship 1 because of the red particles. You need

Spoiler

Ship 2. It is found after defeating the factory boss.