This truly shows that everyone's body is built just a liiiiitttle differently.
Hammer curls is the most natrual curling movement, at least to me. If I spend a couple weeks hitting straight bar barbell curls, my elbows will light up. But hammer curls for whatever feel great. I also am slightly strange in that my upper forearms are just as thick as my biceps. Its not like strange looking, but i look GREAT in those side angle forearm up shots (like everyone does at Expos LOL)...and i swear to god thats from me just not wanting elbow tendonitis and me just hammer curling for years.