Imagine Harry out in the woods, wearing his invisibility cloak, carrying a .50bmg Barrett, turning Deatheaters into pink mist, scratching a lightning bolt into his rifle stock for each kill. I don’t think Madam Pomfrey has any spells that can scrape your brains off of the trees and put you back together after something like that. Voldemort’s wand may be 13.5 inches with a Phoenix-feather core, but Harry’s would be 0.50 inches with a tungsten core. Let’s see Voldy wave his at 3,000 feet per second. Better hope you have some Essence of Dittany for that sucking chest wound.