Here is one I made in agriculture class in high school around 1994 or so. It ain't nothing special, the left side is mostly level, while the right has a deeper cut to it. The point was to hold the long guns level, instead of having them roll over upside down. It works better with bolt actions and such than it does on levers, but that is what I have on it. It also has a door that pulls downward for storage of ammo and such. I mostly posted the pic because I am proud of it's contents, three Marlin rifles just like I like them, with no frame safety, and uncheckered wood. The top one is a model 1893 in 32-40, labelled "For Blackpowder Only." The second from the top is a model 444S, in .444 Marlin, with XS ghost ring sights. The third is a model 39A, that dates to 1980, the year I was born, that I just picked up yesterday, and have fallen for faster than I have for a gun in a long time.
Sorry, that picture wasn't very good, and that is a Sierra bullet poster behind it.