C4 explosives low damage to infantry

I've been trying to use all 3 packs of C4 to drop next to a "Capture" location. The enemy literally has to be on top of all my 3 C4 packs to "hack" the objective. When i activate the trigger, 75% of the time it doesn't kill an enemy. Its absolutely ridiculous. It's enough to blow up a tank into a cloud of fire and dust, but not enough to blow up an infantry soldier. It's either broken and the damage to infantry has to be increased drastically.  Once again, the developers has completely ruined sniper class in this game.