I just purchase the gun racks at Wholesale sports, they're black plastic covered metal and can be screwed into the wall using anchors and such. They're made to use in the back of your truck if you wish, but I guess we can't do that in this fine country anyways...so I use them for my wall. The come in 2 and 3 gun racks....stick them at the desired width and you're good to go.
Ryan