When I was playing ME3 yesterday, I saw something very interesting. One of the players, playing as a turian on Silver, was tearing through all enemies like nothing. Even Atlases and Phantoms only survived at most one second even with activated barrier. He only used his rifle, and one shot seemed to remove about 50 % of the barrier/shield/health.
Even the saber, which is quite strong (but slow), requires around 2 full magazines and several seconds to destroy an atlas.
I certainly wasn't dreaming and tried to find out how he achieved this, but the lobby was closed just when the match ended, so I could not glance at his loadout or further character details. I remember his player name but will not post it here for privacy reasons.
How is this possible? Does this work in a “legal” way?