I swapped the Optics on these two rifles I have, made a world of difference. I had to mount the top one the way it is to get the most comfortable fit, the backup sights actually work quite well in that configuration. Its a older Bushnell Red Dot. The Sig has now the Bushnell .223 Bullet Drop scope, 1-4x power. Couldn't ask for a better fit, I'm wanting to test fire them like now haha.