Shin Ryoku

It's actually called Switch Shots Max.

Link: http://www.ebay.com/...y0AAOSwEetV8U9S

These ones are all purple. Just another option and they are pretty cheap.

I do not have the skill for this mod but from watching the vid, you will need:

Nerf Retaliator-$25

Nerf Rough cut-$20

Screwdriver-(probably have if not go to any hardware store)

Epoxy Putty-$5 to $20

Edit:Hand Saw-$10 to $20

Spray Paint: (prices vary, go to places like autozone to buy a primer and clear coat)

So in total this should cost about $75 or maybe a little more depending on where you get your materials (not including screwdriver or paint) 

And than you will need to do some internal stuff such as integrating the Retaliator handle into the rough cut.

Sorry if this wasn't to helpful due to me not doing the mod.

Hmm. I cant seem to find any big blasts for sale . Are there different gens on the blastzooka?

Could you show a picture of gen 2?

Edit: Is it the green and blue one? If so i think i got it