So I was thinking about making an inline BBMG, but instead of having a spring to push the BB's foward, there would be a plunger. The back would not be capped off, and you would manually push the plunger foward, causing the same effect as the spring. Then my younger brother had a really good idea.
Why not just mod a caulking gun 
I am going to build one, hopefully sooner rater than later. If someone does so or has done so, I would love to see pics!!!

Beware the lollipop of mediocrity. Lick it once and you'll suck forever. -Brian Wilson