Take a look at your pellet boxes, see if one is missing a bunch. If you can't tell... well T7 is hotter than pyrodex. How much difference will it make... ??? I don't know if there is any way to know without shooting it. Its not gonna be so much that you'd miss a deer, but it could possibly make a difference in shot placement. I know for me confidence is huge when in the field. I'd try to go shoot it if you can.