Some people claim they are the same powder, however I'm not one of them.
First, this sounds silly but when I open a pound of H-110, it has a very different smell that a pound of W-296.
Second, when I was working up loads for my SRH .44mag, I bought a pound of each. Using the same grain measurements I loaded up several rounds of each. I got better results from H-110 and have been using it ever since (something like 10-12 years).
To me, they are different. I'm sure one was made to be similar to the other.