Alright sorry for the poor quality photos first off... didnt realize my daughter had gotten a hold of my camera and handled the filter.
I was pretty conservative with the rods and size... pretty small in diameter.
I used a dremel and made a hole just so the rods would barely squeeze in. one on each side. its been painted. I didnt add any epoxy or bondo. like i said pretty conservative. no weight difference really. I also used sand paper on the very front of the stock to open it up just slightly.
I picked the rods up at home depot...im sure you go with a larger gauge. or just add a couple more with some epoxy.
Not even sure if the axis had same stock under barrel but this should get you started with ideas.