Hodgdon powder has listed for the Barnes 250 gr. XPB bullet using h110 27.5 grains to 28.5 grains. Barnes load data lists h110 as 29.5 grains to 32.8 grains. Only difference is primers. How comes such a variation in powder? Which data do I use? I have a BFR in 454. Thanks in advance guys.

It's not uncommon to get big variations in recommended powder weights between bullet and powder manufacturer. In my experience Hodgdon was a lot hotter then the Hornady and I didn't even get to the max load recommended by Hodgdon before quitting and pulling the rest. I don't know which is right, but as always, start out low and work up paying close attention to pressure signs and velocity if you can.

Pressure barrels as well as the test equipment are different. But primers also DO make a difference.

Temps can make a difference with certain powders. They really do, when the temps get 100 or over, here in Texas.

I prefer to go with the bullet manufacturer's book.

I usually concern myself more with accuracy as I am "working up" on any given load. So I have to consider myself in the equation as to how much punishment I can take and still be accurate. Just go slow and pay attention in loading as well as shooting.

Getting Maximun velocity out of any gun pretty much strokes the ego of the shooter. I've always loaded a few grains less than max on every round I load. I Feel it's safer for me and the gun. I've never seen any difference in performance in any animal I've taken from groundhogs to elephant.
Accuracy is far more important to me than velocity.

X2

I will add, though, some of the common magnum pistol powders we use tend to perform better when loaded hotter. H110 is especially known for this.