I need to push in the rocks as each window across the back of the house is tempered double glazed and takes months to have one made, and cost well over $1000ea. Already shot a rock through a sliding door at the old rental. That cost me over $500, as it was single glaze. and it took 8 weeks to get fixed. With windows now taking 5-6 months to be made, last thing I want is to shoot a rock through one. Too many to pick up as the entire block is covered in gravelly sand. Many years ago the sea would have been where our house is now. They call this spot Gravelly Beach because dig down below the surface 150mm and all you get is a gravel sand mix, much like sand and metal concrete mix.