A wadcutter has a full-caliber (or damn close) flat nose (meplat) for max striking power. A SWC has a flat nose, but not full caliber, so has less strking power. The SWC does have a sharp full-caliber shoulder, but depending on the exact bullet used it also has a tapered nose which seems like it would tend to push through tissue like a round nose instead of cutting through like a wadcutter. I used to handload a hardcast 148 gr DEWC for self-defense use, but switched to a soft lead SWC-HP for that little bit more bullet weight and (hopefully) some degree of expansion.