Howdy
At the top of this photo is an older Ruger Three Screw Flat Top 44 Magnum. Note the distinctive three screws in the frame. These were made before Ruger began installing transfer bars inside. No, Ruger never recalled the Three Screw Models, but they will install a transfer bar into the older models, which I DO NOT recommend. Learn to use it properly, only load it with five rounds and never lower the hammer on a live round.
At the bottom of the photo is a "New Model' Ruger Blackhawk chambered for 45 Colt. I also have an auxiliary cylinder for this revolver chambered for 45 ACP, but that is beside the point. Notice there are two pins in the frame, rather than the older Three Screws.
Lets look at the guts of the old Three Screw for a moment. There is no transfer bar anywhere, and although it uses coil springs instead of leaf type springs, the revolver works just like a Colt Single Action Army.
Here is a close up or the lockwork parts of the Three Screw. Notice the hammer has two separate cocking notches. The so called "safety cock" notch at the top, half cock in the middle, and full cock at the bottom. Again, never trust a revolver like this with a live round under the hammer, only load five, and lower the hammer on an empty chamber. And never trust the "Safety Cock" notch. Just like a Colt, If the hammer spur is struck forcefully enough the "Safety Cock" notch can break off, or the tip of the trigger can break off, allowing a round under the hammer to fire.
After some expensive lawsuits, that Ruger lost, filed by idiots who did not understand how to safely shoot a Three Screw, the New Models were made available sometime in the early 1970s, and Ruger stopped making the Three Screws.
Here is my New Model Blackhawk completely disassembled. The long thin part attached to the trigger is the transfer bar. The transfer bar is only in position to "transfer" the hammer blow to the frame mounted firing pin when the trigger is pulled. Otherwise, the transfer bar is lowered and the hammer cannot reach the firing pin. Modern Rugers like this are completely safe to carry fully loaded, with a live round under the hammer, because even if the hammer is struck, it cannot reach the frame mounted firing pin.
Here are the lockwork parts to my New Model Blackhawk. The only cocking notch on the hammer is the full cock notch, there is no "Safety Cock" notch and no half cock notch. To load or unload a New Model Ruger, the loading gate needs to be opened, which frees the cylinder to rotate for unloading and loading.
Here is why you cannot/must not push the velocity in your Uberti Cattleman. All three cylinders in this photo are chambered for 45 Colt. The three cylinders, left to right, are from an Uberti Cattlman (just like yours) a stainless Ruger "original model" Vaquero, and a 2nd Gen Colt. Notice how much thicker the chamber walls are at their thinnest sections on the Ruger cylinder than the other two. This Ruger Vaquero cylinder has the same dimensions as a New Model Blackhawk. I don't recall right now exactly how much metal is between the chambers, but you can see it is visibly more than with the other two cylinders. In addition, Ruger moved the bolt locking slots in their cylinders off center from the center of the chambers. The Uberti and Colt cylinders have the locking slots directly on center with the chambers. This means there is very little metal between the chambers and the locking slots, which makes that the weakest spot in the cylinders. Moving the locking slots off center means there is more metal between the chambers and the locking slots on a Ruger cylinder than either of the other two.
I do not have a copy of your Hornady book, but I have several other loading manuals. Specifically, my 13th edition of the Speer manual has a section just for 45 Colt for Ruger & Contender
ONLY loads. The loads in that section are OK for a modern New Model 45 Colt Ruger. I am not going to give you specific load advice, that is what manuals are for. But you need to be aware that achieving 1000 fps is not the end of the story. Bullet weight has a huge affect on maximum velocity. One weight of bullet might easily do 1000 fps, but a heavier bullet might be a KABOOM waiting to happen.
Again study my first photo. The older Three Screw Rugers are easy to identify, and tell apart from a modern New Model Ruger.