A couple of weeks back I needed to show a few targets used with my carry firearms for my application for a new CCW in a new jurisdiction. I used a SEARS tool bag made of sturdy canvas and webbing straps. I bought it when it was on sale for either 10 or 12 bucks. I carried, three hand guns, clening eqipment and two sets of hearing protectors and eye protection as well as 150 rounds of ammo. The price was right and the bag did not scream "Gun" or "LEO" either. Te bag is about 20 inches long and mybe a foot wide and has a sturdy zipper.
Recently SEARS had a sale of a small tool bag that is 12 inches long by 8 inches wide and maybe 10 inches high with a good zipper. The nylon material with padded bottom section was black in color and only 5 versus 10 bucks. It would make an excellent dedicated carryall for a defense weapon with all spares, ammo and a holster and ammo for ether range use or "grab and go kit" in case of emergency.