I've cut the window from Lexan. It's tougher than plexiglass/acrylic, but 2 or 3 times more expensive. It won't shatter or crack "easily" You can buy Lexan sheets at Home Depot, Lowes and some hardware stores like Ace.
The window will be fastened with 1/4" socket head screws, for reinforced armour look
Using center punch to mark each fastener hole.
Roper Whitney No. 5 Jr Hand Punch kit available here
Hand punch (estimate $60 new)
"Look Ma, No deburring needed!"
The benefit of using Lexan is that you can drill or hand punch it without cracking it.
Clean hole cut! I love Lexan.
Ironically our concept drawing calls for bullet holes in the Lexan "bullet proof" window...lol