It was GURPS Super game, with 500 PC characters.
My character did not have any offensive power, but was a decent shooter, although without any superpowers linked to it.
The big bad guy was ultrafast running up and down buildings.
Me: "Well, I load a 6th bullet in my gun and shoot" (my PC was careful and was only having 5 bullets in his gun, to prevent from shooting himself accidentally).
DM: "X malus because of speed, distance,..."
Me: 3 (on 3d6), "err... crit, I hit"
DM: "Grumph, ok, roll location"
Me: 4 (on 3d6), "err... head shot"
DM: "Grrrrrumph, ok, roll crit effect"
Me: 18 (I believe, memory a bit fuzzy), "err... negate all armor", followed by significant damage.
DM: "You killed my 900 points NPC".
Never, never underestimate the power of a .357 Magnum. It might not be the most powerful gun, but it is the deadliest as far as I know ;-)