Capacity: 8
That's dumb.
I had a Taurus 94 for awhile, and the 9 shot cylinder was at first attractive... then, annoying.
It ain't a defensive gun. Capacity just doesn't matter. Part of the trigger stroke wasn't the "same" (when used as a DA training aid for a .38/.357 defensive revolvers) due to the lack of motion of the cylinder (...and the rest of the trigger stroke sucked just because it was a Taurus 94, but that's irrelevant to discussion of this new Ruger). The 94 cylinder only moved 40 degrees per trigger pull. The typical 6-shot K/L/GP frame moves 60 degrees per trigger pull.
DA .22 "trainer" guns should have 6 shot cylinders.
As-is, this gun has no HKS or other brand speedloaders available for it due to this decision.
With 6 chambers, the HKS 22-J speedloader would be compatible. In fact, the OLD SP101 .22 used to have 6 holes, and HKS markets the 22-J as compatible with "the SP101". Now, this 8-shot variant ruins that and just creates more weirdness and caveat and non-standard oddities for shooters to learn... is your gun an "old" SP101 or a "new" SP101?
I do like the front sight, though. Big fan of green fiber optic front sights. Got 'em on both my Redhawks, my Buckmark, my CZ and XD9. Need to get 'em installed on my 1911's, but unlikely they'll ever get installed on my K-frame, J-frame or SP101 .357.
All in all, I'll keep my money in reserve for a chance at an older SP101 with a 6-shot cylinder.
ETA: Also, in my experience, tiny framed guns have heavier hammer springs than heavier framed guns. Given the additional hammer energy needed anyways for a rimfire round to ignite versus a centerfire primer, that means that a J/SP frame is a rough trigger to begin with... and just going to be rougher due to the heavier hammer spring added to it for rimfire shooting. Would have been much smarter for Ruger to either re-start the "Security" frame again for the .22, or offer this in a GP frame rather than SP frame.
Larger frame = longer pivot axis for the hammer = greater velocity and mass of the hammer for less spring strength.
Heck, build a .22 on a Redhawk. It'd be one baby-soft DA trigger.