Why does my primary feel so weak compared to my warframe and melee

I’m MR7 and I swear primaries feel so much weaker then my frame and melee I’m pretty sure I’m modding correctly i checked guides and they already match what I have I don’t have any fancy rivens or galvanized mods but on my hek/drakgoon/soma but I can get 3-4 enemies per mag while I can just press 3 w my gauss or use my melee a couple of times and get a better result. Is there any weapon I should be using? Am I modding right? Do I just need to grind MR or rivens?