If you don't know what I'm talking about, check out this thread Bob posted.
I picked up a Cobra at Lowe's a week ago and decided to see if I could make them the ultimate defend the core weapon. I think I've achieved that task. Here's what I did to it.
The first thing I wanted to try was creating the ultimate ball gun.

Nothing special here, I just added a 1.5" PVC coupler and put on a 5" segment of PVC. I'm using the practice gold balls you can find at Target. Thanks to Draconis for helping me with this.
Results are mediocre in my opinion. It shoots a single ball around 45-50'. But this is where it gets fun. When I went to Armageddon this year, Bags was using a signal launcher for a ball gun. He would load one ball, then a bunch of 1/2" stefans, and then another ball on top. Look at this video. (I put five darts in there)
As you can see, there is at least a ten foot spread that shoots all the projectiles at 40-50'. I'd like to try a longer barrel and see if I can jam more darts and balls.
But that's not all. I wanted to experiment with 1" foam backer rod like Forsaken did with his Mongo Titan.

I am shooting these. They are two and a half inches long with three 1/4" slingshot weights. I tried four, but it was way too heavy. Another thing that is noteworthy, is that these darts are incredibly durable. You can see these darts are quite smashed up from slamming against the wooden fence.

Compared to a 1/2" stefan.

These darts fly 80-90' with 20 pumps. With 10 pumps, they shoot about half as far. Here's the video.
Since the balls seemed to shoot just as far if I loaded more than one, I tried the same thing. I was quite surprised.
Shooting two 1" darts and three 1/2" darts
Shooting three 1" darts
If you notice in the last video, the three darts hit the fence at the exact same time. The range with the three darts only dropped 10' in range with a nice little 5' spread. The 1" darts plus the 1/2" darts had a 10' spread at about 70'.
When you add more darts, the range only drops a couple feet for each one you load. Anything more than five of them, the blaster won't shoot all the darts.
I plan on experimenting more with the 1" darts like changing barrel length, weight, and other shit. But thus far, I'm pretty satisfied with the results.
Now I command all of you go out and get one. I am having so much fun with this.
Enjoy.