Here's a quick guide to understanding Taurus frame sizes:
605: J-frame sized. Takes the same loaders, fits the same holsters. Same is true for the 905 just in 9mm.
856: Colt D-frame-ish sized, generally takes most K-frame speed loaders. Fits some J-frame holsters, fits almost all SP101 holsters/K6 holsters.
65/82: Takes K-frame loaders but are closer to L-frame in external dimensions.
66 7-shot: Takes 586/686+ loaders and fits similar holsters
608: approximately N-frame sized, but has its own cylinder charge hole pattern
Trackers: Fits L-frame holsters, and generally takes the same loaders as equivalent caliber L-frames. My 692 tracker shares 7 shot loaders with the Taurus 66 and my 586 L-Comp.