Is it a Ruger brand grip frame or an after market?
Which "new style" Ruger do you have?
If it's a NM Flat Top Blackhawk or New Vaquero it has the Ruger Reverse Indexing Pawl System and there is one slight modification you'll need to make to the grip frame for the cyl pawl to work properly.
Kind of OT but I just had a heck of a time trying to fit one of those "Vaquero Lightning" grip frames to my Single Six fixed sight.......
After 30 minutes of filing, finally got it to sit flush, and then found out the cylinder stop plunger hole was drilled too small and crooked.........so now my plunger is stuck in that hole...my last hope is to open the hole up a little and try it again, once I get the stuck plunger out.
And......Midway lists that plunger as "discontinued",because I'm likely to have to either get a new one to use the original alloy grip frame, or destroy the plunger because I'm going to have to use vise grips to get it out.
I think these are made in India or something, a gun shop who sells on GunBroker had a bunch of them but they mysteriously ended all the listings, maybe because people were having problems fitting them. They claim "drop in fit" but it was far from drop in....maybe, I can salvage the frame and still use it, because it looks great, but hopefully I can get it working. The Single Six is just a plinker and I wanted to make it a little more fun to shoot and look at, but it's way more of a PITA than I thought.