most of the time its his 6D, the one where he turns around and kicks, that is punishable in a block string if he uses it, 3C will stuff it everytime, and depending on how close he is you can go into a 214A combo instead of tossing 236D, IB'ing isn't necessary.
The most important part about fighting a bang is going off of what he's doing, not what you think he's going to do, he has a lot of mixup and do the most you can to stay as far away from the corner as possible, running around a lot to get him to waste nails is a great strategy, once bang is out of nails, his ability to get closer to you is cut by 80%.
And to reiterate, any combo that ends in a knockdown, use a gravity pit and place it in front of him, placing it on top gives him the chance to roll out of it most of the time. Personally i think bang is one of V's hardest matchups when the bang isn't a moron, 10stars destroys me constantly with his bang because of how easy it is to close the gap with Dnails and pressure me into the corner.