question about X2

I don't know if anyone has asked this before, but in X2 when wolverine gets shot, why does it take him so long to heal? wouldn't you think the bullet would bounce off his adamantium skull? it looks like in the movie it penetrated right through. and theres a thin layer of skin and then your skull bone is right there so if it was metal you wouldn't even think he would be knocked out from it

A, bullets themselves arnt that big, 9mm i think the cops used in that scene
B,there is about a centimeter of skin/tissue before ur skull which wud indeffinetly slow the bullet
C, with the skin/tissue before the skull the bullet would have crumpled and not rebonded
D, his regenerative powers (although sumtimes shown) are not that quick

plus, the force of the hit will cause severe brain damage........................

oh ye dint think of that one willrules