I made my current reloading benches 24" deep x 8' long, and my gun cleaning/gunsmithing bench is a full 48" across x 8' long. The 2 reloading benches sit against the wall, while the gunsmith bench sits out in the middle of the floor. I made the frames out of 2x6 and the legs are 4x4's. The reloading bench tops are 2 layers of 3/4" plywood, and the gunsmith bench is 1 layer of 3/4" plywood and a top layer of Omega wood (it has an aluminum top layer).
The reloading bench framework
The gunsmith bench framework, the close end is built up with 4x4's as my large bench vice will go on this end.
The mostly finished gunsmith bench (still needs bottom shelf), with the reloading benches in the background.
The vice sitting on bench, before getting bolted down on corner.
Even the narrow 24" benches are heavy enough that they don't budge during use. These were all built in place in my basement, and will stay here if I ever move. I prefer the 24" depth on this type of bench, as any deeper just collects clutter and is inefficient. But with 16' of bench space for reloading, I kind of have room to spare for now. On the gunsmith bench, yes it's 48" across, but being in the center of the floor, I can and do walk and work all the way around it, so the extra width actually comes in handy.
Thanks for looking.