As far as I know, full moon clips are only for rimless ammunition, like .45 ACP or 9mm. Rimmed ammunition, like .44 Special, works with speedloaders. HKS makes speedloaders for 5 shot .44 Specials. I have two for my Rossi 720 and they've worked just fine.
Now there are full moon clips for .38 Super, .38 Special, .357 Magnum, etc. I did find out that S&W makes moon clips and de-mooners, and another organization, name escapes me at the moment, makes the whole variety of moon clips as well. Of course Dillon and Brownells carries them, but I just wasn't sure about the .44. I have an HSK speedloader for my 696 and it works, it's just that moon clips are so much faster, nothing to get rid of when you load. Just load and shoot as fast as you can squeeze the "go button."
There a great article in the latest Handloader on the new S&W 627-4 "Hotrod" 8 shot .38 Super revolver with moon clips, it's faster than an autoloader.