For that one, you can use loose rounds, speedloaders, or moonclips interchangeably for 38 and 357 (rimmed case).
For 38 Super, you would have to use moonclips for 9mm (semi rim). Some 38 Super ammo will fit in a 357 chamber. Usually this will be new factory ammo or new unfired brass. If you only fire it in the revolver, you can probably reload it and keep going.