I'll give you the most OP trick to fight charged elites and snipers so you never ever ever loose against them anymore, pay attention cause after you do this simple trick the whole Elite crew will hate you!
Whenever you see a heavy charged elite, jump somewhere higher in the map for example a box in the map(there're a lot of these high places for a reason, map designers aren't crazy yooo), and use your gun to pew pew pew him down from higher ground, you can also wait up there until their buff runs out, then you can proceed to melee them for a more easy kill that doesn't waste bullets!!! How hard it that?!!, for snipers, shoot them pew pew pew from afar until they are wounded, then finish them with a melee execution!!, for shotgun elites, you can wound them from afar with your pew pew and secure a kill or you can time a grab right after they call their airstrike so you don't waste bullets as well!!, Now charged elites will hate you for this!! Be careful cause they'll send you a whole team of charged elites to your house now!!