The nuts should be on the left side of the firearm if your are looking at it from the recoil pad end. The cut out is designed to be a positive stop when the rifle recoils. There are instructions provided with the rings that explain all of this. When the rifle recoils, its natural direction of movement is towards the shooter. However, while the rifle is recoiling in a backwards type motion, the scope will want to stay static. Therefore it will have a perceived forward motion. With the nuts on the left side this places the cutout on the bar towards the muzzle of the rifle. when mounting your rings you will want to slide them all the way forward(towards the muzzle) in the picatinny rail notch. This way under heavy recoil you will have a solid mount for your optics. In process of thought it seems backwards but it is right.