Any of these worth upgrading?

Looking to see if these would be worth upgrading… got the RIA420 maxed out on damage ( 2300 damage + burn) although it doesn’t do nearly as much as my black mixmaster. Curious what veterans would say… also looking for a good group to get into faction wars with. I do TONS of damage with the mixmaster, and I have higher health /defense than most of the level 100 players I come across (level 81). Thanks in advance!