Tunnelling with objects heavier than about 0.01

[FailMaT_T]

I'm currently experiencing an issue where rigid body cubes with a weight greater than an order of magnitude of 0.01 (ie 0.1, 1, etc) pass through static rigid bodies that make up the world map. When they hit walls they spin violently and enter the walls which is undesirable of course. Does anyone have any suggestions as to why this may be happening?

Thanks

Matthew