Hit boxes?

So i made a model for a window its its hard to tell how it looks but basically its 16 wide and 32 tall and sits in the center of a block so the bounding box is all messed up i have it set to 16 wide and 32 tall so it fits in a 1X2 hole in a wall but if i hit the lower part it breaks like normal but i hit the top and it wont break it. And if make a 1x1 hole it still places it i tried tinkering with it but if i change the bounding box more in game its just gone i will have a block i cant brake and walk through.