Visiting my M8 Tuesday to put another roof ( tarp ) on the shot shed, i found a tire thread a truck had thrown off, i picked it up CUZ i think it will be excellent for a pellet trap.
It will be " fun " cutting it into smaller pieces though, CUZ i cant see any other tool we have for doing it other than a angle grinder, and that in thick rubber got to be tricky.
I am a little on the back foot about how to mount it, i think if you just use it as a backing on a sloped angle like your trap, well as it is rubber it might just be kicked strait back out of the trap rather than getting deflected down.
So i have contemplated smaller strips of it that can flex a little when hit and then just " drop " the pellet strait down
It will of course necessitate a trap that is somewhat oversized to make things fit, but i am OK with that as it will not be moveable, or at least not without a ATV