Mini gun improvement?

[dupsnug1999]

Hello gun maniacs! My question is can improve my mini spuf, bb, combustion cannon. I use 100 ml bottle with straw for the barrel that fits bbs. I fill the bottle with propane/butane from gas filler and it is 3 % from the 100 ml bottle. So can improve it like reducing the size of the container make it larger or something else i dont know. Here is the link for more details http://youtu.be/wjyudsQHVKk