Hi-Speed is Remington-speak for .38-44. And so is Super Speed (Winchester) and Super-X (Western). None of those have been loaded since the early 1970s. If you want to use those, the only way is to find some antique ammo or roll your own.

I had a Llama .38 Special revolver (2") many years ago, and it was a good gun. Very much like a K-frame S&W except for an in-frame firing pin. Sort of sorry I sold it over 20 years ago.