Hey guys, if you want a really effective way to use the Jet Gun I saw in this video (where he was on round 100) that he's able to use it constantly by switching to it and switching back to another weapon.
Here's the link (skip to around 2:45 for his jet gun method):
(It's not the best quality, I think he was just recording his screen with a camera?)
Edit: Oh a warning, he posts a "picture" just before that, might give you a little scare haha.
http://www.youtube.com/watch?v=09wtQzheR4Y
I hope it helps guys!
Side note:
This was probably the best thing BirdDog Dan posted, he mentioned CrowdControl Zombies so I started looking for them and came across this video. From what I've seen of their videos, they don't have anything related to the easter egg as he suggested. Just high rounds.
- Wallaby