I can glitch under and through almost anything by using the step over key. It should work one-hundred percent of the time with the same model as long as the ground is low enough.

http://www.youtube.com/watch?v=dJE4WD8lZIw

http://www.youtube.com/watch?v=wknUuEPFyp4

http://www.youtube.com/watch?v=WfugIFiLAVg

http://www.youtube.com/watch?v=CVqAngobWQw

This is an office building in the center of Elektrozavodsk. I was randomly teleported.
http://www.youtube.com/watch?v=MNEcVqQdaSU

This is a building in the airfield near Balota. I was watching the staircase and my friend was watching the door. I was killed by someone who glitched through the wall.
http://www.youtube.com/watch?v=_Ilu0Zd0M84