Okay, let's take Mass Effect 2, and its painfully underwhelming arsenal in all its glory: It had an assault rifle, a machine gun, a battle rifle, and so and so forth. We're going to do something very simple with it: we're going to take the Spectre-specialty AR from ME1 and put it in. Its stats are as follows:
This gun can fire for thirty straight seconds at a rate of three bullets a second without needing a reload
It keeps recoil to a nonexistent level for twenty-five of those thirty
It chops off 365 hit points with every shot (triple critical on headshots)
It has a spread rate of exactly 0.0 (perfect accuracy)
It has an optional zoom level of 2X
And it reloads in just under a second.
I like to call it 'The Game Breaker'. Believe it or not, it actually was in the first game (spectre assault rifle with 2 kinetic stabilizers grade 8). when equipped with level 8 tugentstein rounds, it could kill a geth armature in just under two clips by itself.