Inferno is a game mode based around primary usage due to the lack of special ammo during the first portion of the match. Though special starts to come into play there are many ways to counter a sniper or shotgunner. Yes a lot of people use snipers because of the hype aa and time to kill. If you want to be killed less by snipers try to use armor piercing rounds or stay out of sniper lanes. Another good option is to use your vertical space; as in jumping over the sniper to get first shot. Also all of the classes have a special movement ability. Using that ability while crossing sight lines greatly decreases the chance of a sniper getting a killing blow. High impact scout rifles can also help a lot. They cause loads of flinch and are optimal at sniper range. Even a MIDA can deter a sniper from poking out. Depending on your class you can use a certain perk combination to your advantage. You can you juggernaut on a Titan to give you immunity while running towards the sniper. I hope this helps.