The law is against magazines holding more than 7 rounds. Magazines.
Tom, I'm going to have to play devil's advocate here.
The law doesn't simply restrict magazines; it restricts "large capacity ammunition feeding devices"
, which are defined as...
...a magazine, belt, drum, feed strip, or similar device, manufactured after September thirteenth, nineteen hundred ninety-four, that (a) has a capacity of, or that can be readily restored or converted to accept, more than ten rounds of ammunition, or (b) contains more than seven rounds of ammunition, or (c) is obtained after the effective date of the chapter of the laws of two thousand thirteen which amended this subdivision and has a capacity of, or that can be readily restored or converted to accept, more than seven rounds of ammunition; provided, however, that such term does not include an attached tubular device designed to accept, and capable of operating only with, .22 caliber rimfire ammunition or a feeding device that is a curio or relic... (definition of curio or relic omitted for brevity)
My argument is that a revolver cylinder is similar enough to a "drum" that it may fall under the definition of an "ammunition feeding device", if the NYSP takes a hard line in their interpretation of this provision, which I suspect they will.
The good news is that AFAIK hardly any revolvers with a capacity of over 10 rounds even exist, and current 8-10 shot revolvers in NY will be grandfathered.
I do, however, believe that revolvers like the S&W Model 627 (8-shot) and Ruger Single Ten (10-shot) are now verboten
for new commercial sale in NY.