I guess I'm bias. Here is my latest harvest of horns from a few local slaughter houses here in Thailand.
![](http://i244.photobucket.com/albums/gg15/bamboo_archer/horns_zps58e3fdc5.jpg)
I would say if you are going to make a pvc bow go for it but I couldn't imagine going to the work to do a wood core and sinew and use pvc for the belly.