I, too, have a fat hand (some say I have a fat head too), and I suffer from hammer bite with the Colt 45, but not the HSc. I pretty much have to have a beavertail grip safety on a 45 or I'm going to lose some blueing to blood. It's hard for me to understand how it happens with the HSc, as the hammer thumbpiece is so small and seems to me to be located pretty far above my hand.