I had the same experience with two mail order BPs from a big online breeder (my first two). Both were extremely snappy out of the box and one spent the whole week striking from inside his cage even if you entered the room. I think their fear level was pretty raised from the whole process of being bulk bred and shipped.
After moving them to smaller tubs and giving them some time (actually less handling) to fully calm down and relax in their environment, they have changed personalities 180 degrees in a month.
They still are a bit more head shy, but are much more calm and haven't taken up the defensive striking pose in weeks. Now they will actually become curious and wander around and let me pet their heads. I was pretty despondent the first couple weeks though because every time I held them it was either trying to strike or frantically trying to run away and escape my grip.