I've just started looking into gun racks. The company Great Day keeps popping up. I want to hear from people that have actually used them in a 2021 Sierra at4 with a sunroof. I may just go with something that attaches to the back of the front seats like the picture you posted.
Let me know what you come up with. Thank you
Years ago I had one made by Big Sky in a F250, no sun roof single cab- awesome setup gun secure and handy. Later put same brand in a F350 with sun roof, as I recall, it mounted on sides of cab. I know that no help for your current truck but just sayin. In my current AT4x- I have the under seat storage sold by GM. I know not super handy, but great setup for- hidden, protected scopes from folks and/or dogs in back seat.