The Pitbull series of revolvers are chambered for rimless cartridges but are configured so that moon clips are not needed. Most revolver speed loaders rely on gravity, once the cartridges are released, to fully chamber the rounds. Even those like Safariland Comp III\'s or Jet Loaders do not have a strong enough spring to overcome the extractor mechanism that is necessary to make the Pitbulls moon clip free. So the answer to your question is that there are no speed loaders that will work with the Pitbull series of revolvers.
The above is really moot since nobody makes speed loaders for any rimless round - regardless of the type of extractor or number of rounds in the cylinder .

Uplula works good for me.

I found that charter arms makes one for all calibers for your choosen pistol call the HKS speed loader

Uplula for sure!!

I have found Maglula UpLULA™ Pistol Magazine Loaders to be the best.