DC
2 high power rubber bands

First, put the 2 rubber bands on the blaster like so:

Then, extend them down to the handle and your done!:

Here it is pulled back:

Next to my modded-in-two seconds NF:

It gets ranges of about 50 ft. flat considering mine is CPVC'd but it's horribly inaccurate and impractical for wars. Seeya all!