[Assault Pioneer]

Hi.

I got a custom project where I want to customize the magazine catch on a M4, the plan it so file down the edges at the bottom of the mag catch till their flush, and put plastic card on top of the original reciever to extend it or give it a new shape, I got a design to make the body unique and have made a template using a cut up dvd box and it all fits I just have to glue it on, sand and paint to make it look good but the dvd box plastic is kindof weak in my opinion I need something more rigid. plus it still looks like I have a card ontop of the reciever I need like a shaping putty or like drywall stuff to smooth out the edges to make it look natural.

So does any one know of a strong plastic card that about as thick as dvd cover plastic that I could use in a game and not have to worry about it breaking? also does anyone know of a putty so I can like "drywall" it and sand it down paint over and no one would know that the extra layer of plastic was there? like I shaped the original plastic? its gotta be strong and not flake off though.

thanks

EDIT: Does anyone do custom plastic work? like molding/custom design/prototypes etc?