Bullet penetration not working properly

I've tested guns up to the sniper rifle shooting at thin wooden structures, cardboard boxes and plastic chairs on siege of Cairo.

 The penetration is inconsistent usually there is no exit bullet hole in these structures or holes on the surfaces behind them. Sometimes the damage is carried on anyway (ie. blowing up two cardboard boxes in a row) but with some wood structures and plastic chairs the props behind them seemed to take 0 dmg even with base sniper rifle rounds. This could be very frustrating in actual gunfights.

I only started testing this because my dmr didn't seem to be punching through a flimsy wooden screen as i was being pushed by someone. 

Otherwise gunplay is feeling great, hope someone will give this stuff a pass over before release.