Small rounds with a punch.
Available and relatively cheap ammo.
I don't have one, but I want one.
No moon clips!
I am not a Mooney!
Should have said- I want a J Frame.
And how, pray tell, do you intend to shoot rimless ammunition in a revolver without them? Sure, it'll work sometimes, but it's no fun going bang, click, click, bang, click, click.
If you think that you don’t need to use moon clips for rimless pistol calibers in a revolver – you’re wrong. You are correct in assuming the shoulder in the chamber is there for headspacing purposes. However, since SAAMI sets the specs for cartridge dimensions, the shoulder is placed at maximum case length depth for a given caliber. My experience has been that any factory ammo or brass, when new, is always considerably less than this dimension - meaning that, in reality, headspacing on that shoulder, by the case mouth, seldom actually occurs.
What does happen is that variances in chamber roundness, smoothness, cleanliness and other variables, will hold some cartridges firmly enough that a firing pin strike will ignite the primers. Others are driven forward in the chamber, which results in a light primer strike and a failure to ignite.
Just as some rounds are held tightly enough for ignition and others are driven forward, some cases may drop out of the cylinder from gravity, while others may be "pluckable" and yet others will have to be poked out using a rod.
You should consider moon clips essential for any revolver that is chambered for a rimless or semi-rimmed round. The other alternative is using the rimmed version of that round, if one exists.
The above, of course, does not apply to model 547's, Korths, single action revolvers and Charter Arms Pit Bulls.
OP: The 8-shot 9 mm revolver (model 929) is great for the gun gamers (IDPA, USPSA and Steel) and they have embraced it mightily. It allows non-reloaders to be competitive with all those guys shooting 627's with handloaded .38 Short or Long Colt cartridges.
We're still trying to figure out what the 986 is for. LOL.
Adios,
Pizza Bob