Until F3, supermutants carry big guns and energy weapons. The ones in F3 however use... mostly hunting rifles. They are better off rushing with their fists. With a mod, I've finally fought a supermutant carrying heavy weapons, and it was awesome. I shot him with a rocket, and he shot a rocket right back! That was insanely cool. Then he pulled out a flamer, and I shat my pants. It was awesome. They are walking tanks and can blast like one. Goddamn Bethesda ruined something awesome. Goddamn lame supermutants with hunting rifles.