Auto Trapper - The Auto Trapper was added in the game August 15th, 2016. It looks like the trapper, but has a Auto Gunner-like turret on top. This turret can not be controlled, as it will automatically target nearby mobs and enemies.
Build a wall: One of the most well known strategies/tactics for all trapper classes:
Start to shoot traps/mines out on front of you to make a circle (or enough for you to put yourself in) and get inside it. It's called "The Base".
Shoot traps/mines in the direction you want, try to spray up and down rapidly in until it looks like an arc. It's called "The Wall".
Finally, the "Wall" is made and can protect you from incoming bullets at the opposite side of the wall. If you get flanked from behind, you just simply walk to the other side of the wall.
Note that you can push the wall by creeping slowly while maintaining the wall by shooting traps/mines into it.