Switching weapons constantly isn't as good as a 3 round burst with infinity, It sounds you didn't even upgrade the infinity and are just working off the base model. There is a reason the thing was nerfed to begin with, and it still is a great close range weapon. Out of all the exotic bounty weapon only the infinity is actually good, BadJuJu, Thorn, Super Good Advice, and Invective aren't the best. But Invective is still decent pvp under the right hands.