This happened to me and another hunter during a round. Marines are able to shoot past girdlers as long as they are right next to them, or if there's a table next to them. Basically, because bullets spawn infront of the marines, and if there's already a wall infront of them, it moves across to the next open space which then allows aliens to be shot without fear of death as aliens cannot hit them in return(A wall in the way and a girdle).
Steps to reproduce:
1. Build a wall infront of you and place a girdle next to you.
2. Stand next to it or if there's a table next to it, climb onto it.
3. Start firing through the girdle.
http://s22.postimg.org/tfob7etd9/Girdle.png
Alex Metzer starts climbing onto the wooden table!
Alex Metzer climbs onto the wooden table!
Alex Metzer fires the 44 Magnum!
Carrier (123) is hit by the revolver bullet in the chest!
Alex Metzer starts climbing onto the wooden table!
Alex Metzer climbs onto the wooden table!
Alex Metzer fires the 44 Magnum!
Carrier (123) is hit by the revolver bullet in the chest!
Alex Metzer fires the 44 Magnum!
Carrier (123) is hit by the revolver bullet in the chest!
Alex Metzer fires the 44 Magnum!
Carrier (123) is hit by the revolver bullet in the chest!