its hard to take objectives like B with a sniper because its usually in a small room full of shotgunners. I find using a shotgun benefits you more for objective games and staying alive in general, primarys do not have the time to kill to stop a shotgunner from closing the gap, so its best to use a shotgun to counter a shotgun rusher. I find that trying to snipe a rushing shotguner is very risky and very inconsistant so i stay away from sniping.