You may want to also consider Track of The Wolf nipples. They are a little cheaper, and if they are anything like the ones I bought for my Ruger they are designed with a similar interior as the ones you mentioned. Mine are great and the savings paid for the shipping.
For a Ruger they have Ruger outside dimensions and inside Treso dimensions.
TOW, Possibles Shop, VTI, Numrich, Dixie Gun Works, Deer Creek and Jedediah Starr Trading CO are places to look. I'm sure there are many others also.
I use and like Treso/Ampco nipples, been a bit since I purchased any. They seem to last.
