All armor types seem to have the same protection.

I was testing the different armor protection values in 1.9, mainly for UHCs (Testing to see what level of protection on iron is equal to unenchanted/prot I diamond armor)
I found that all armors give the same protection. (unenchanted iron = unenchanted diamond. Prot 1 iron = Prot 1 dia Etc.)
Here's a video I recorded about this bug. https://www.youtube.com/watch?v=ts5SFwK_rIs