Not trying to be an asshole or anything, but, NerfOmania has already made this. Take a look at his Pumpsnap 3.0. You do have some changes, though.
Yes I realize the idea of a pump snap had been around for a while, but none of the designs completely satisfied me so I decided to make my own revision.
I have a few questions.
Is your pump grip 1.5" PVC?
Is the aluminum 1/8" thick?
What type of PVC is the stock made out of?
The pump grip is 2" PVC and the aluminum is 1/8" thick and 3/4" wide. These two things are crucial to having it fit together- the pump must fit around the aluminum plates while the aluminum plate must fit though the 1" PVC guides on the side. As for the stock, it is made from 3/4" PVC.