It's not info they list, but i would guess it to be right around 5 degrees.

From Titleist: We made the decision not to include the bounce angle because the modern sole design is so much more than just the bounce angle. Given that sole width, camber, grind, bounce as well as CG will all have an impact on how your irons move through the turf it was no longer as relevant to list just the bounce.

I wouldn't be concerned with the bounce- there is the measured bounce and effective bounce- if you have two irons with the same measured bounce but different sole widths they would have different effective bounces. If you are concerned with the change in bounce while changing the loft I suspect if you stay within Titleist's +/- 2 degrees recommendation you would not have any issues.