I believe there are two frame sizes now, the older New Model Blackhawk, and the more recent flat top Blackhawk frame. The flat top is smaller than the NMBH frame, and not quite as strong. If you are intending to load .45 Colt to "Ruger Only" pressures, go with the NMBH, not the Flat Top.Are the new 45 blackhawk's as strong as they used to be or are the frames different now?
Similarly, here are photos of a New Model Blackhawk in 45 colt and a New Vaquero in 45 Colt. Note the thinner cylinder walls. I measured the Blackhawk cylinder walls at about .060 and the New Vaquero Birdshead from Talo at about .040.It is mainly the cylinder in 45. Below is a new Lipsey flat top convertible in 45/45ACP.
Besides being slightly shorter the new cylinder has thinner wals than the older Rugers in 45
According to my micrometer, the thinnest part of the New Vaquero cylinder are the interior walls between each of the six charge holes. At the rear of the cylinder (near the pawl) all of the charge hole walls are thinner. Charge hole bore is larger here vs. the front where the throat bore diameter is narrower. Walls between charge holes and the outside surface (between the flutes) are markedly thicker than the interior walls between each hole.so, where is the thinnest part of the cylinder?