Beretta and .357
These two guns chamber all three of the most common centerfire cartridges-- 9mm, .357 and .38 spl. They have the same nominal "caliber"-- i.e., bullet diameter-- and can both use the same cleaning materials, the same size patches, plugs, etc. The essentials for cleaning-- including a tiny bottle of Breakfree CLP-- can be shoved into a large pocketknife sheath. AND you can get a .22 conversion for the Beretta.