Bella said:
The 45 doesn't stand a just being compared to the 357 or 44.
This couldn't be further from the truth. Many people see the weak .45 Colt loads and assume that's the standard across the board for the round. S&W DA revolvers, Colt SAA's, and the Ruger New Model Vaquero can only handle standard pressure .45 Colt rounds which is why many ammunition manufacturers put out weak .45 Colt loads. Although there are several .45 revolvers that can handle .45 Colt loads on par with the .44 magnum.
As long as you don't use the weak .45 Colt loads, a good hard cast wadcutter .45 Colt round makes an excellent round for deer, and will easily outperform a .357.
Keep in mind, the Ruger New Vaquero can only handle standard pressure .45 Colt loads. Even so Buffalo Bore makes a great standard pressure hard cast wadcutter .45 Colt. The Vaqueros have fixed sights though, something you may not want for deer hunting.
https://www.buffalobore.com/index.php?l=product_detail&p=268
The Ruger Blackhawk which has adjustable sights, old model Vaquero which is built on a larger frame than the New model, or the DA Ruger Redhawk can handle the hot and heavy .45 Colt loads which are on par with .44 Magnum.
This would make a excellent round for deer which is perfectly safe in the guns mentioned above.
https://www.buffalobore.com/index.php?l=product_detail&p=38
Remember, the NEW model Vaquero, Colt SAA's, and S&W DA revolvers can not handle these +P .45 Colt loads safely.
Personally I would go with a Ruger Blackhawk since you want a single action. It will handle the heavy +P .45 Colt loads and has the benefit of adjustable sights.