This walkthrough will help you find Hicks's Shotgun, a legendary shotgun in Aliens: Colonial Marines
1) You have to be in the mission Distress - This it the very first mission of the game
2) The current objective will be to Get to the cargo bay to aid with the cas-evac.
3) Follow O'Neal up the platform around the Gravity Well:
4) Arrive at this door:
5) Go up some stairs, a Xeno will pop on you from the ceiling:
6) Go up some more stairs:
7) There will be a door straight ahead with a white fluorescent light on it. Do NOT go through that door, and instead turn RIGHT, as seen in the screenshot below:
8) This is the door you want to go through:
9) Turn left immediately through another doorway
10) Find the Shotgun on the floor of a big room:
To see full stats, see here: