Sorry i cant see your demo (because work) but I tried a few things.
I made a "pipe" from tilemap that goes around and around.
I fired a bullet into it an an angle and....
Using on bullet step is overlapping surface > bounce off surface
the first few bounces are always flawless even at speeds of 10000s
but over speed of 1700 the 5th 6h 7th plus bounces seem to fail and the bounce dosent register.
below around 1700 though it works really well and the bullet goes around and around bouncing off the sides for ever. edit but at this speed you dont really need to use bullet stepping.
interesting it seems stepping it should work better but maybe it cant take the constant checks for multiple consecutive bounces., I will try a few more things later.
aside... over 1700 the speed makes difficult to track with eye, are you sure you need such a high speed??