What are the differences? Rugers's web site does not say much at all except that the new moder is designed to bring out the full potential out of the .44 Mag. So is the new model stronger for otter .44 mags then the old SBH? What are main differences between the 2? Thank you!

The Old Models have the traditional hammer and firing pin resting on a loaded chamber if you carry and full 6 rounds in the cylinder. This is a no-no as some pistols have discharged when dropped on the hammer, So the traditional solution was to carry only five rounds in the cylinder and let the hammer rest on an empty chamber.

The New Model uses a trasfer bar system that allows the cylinder to carry a full six rounds and for all chambers to be full. The transfer bar keeps the hammer and firing pin off of the loaded chamber until the trigger is fully pulled to the rear. So the gun will not discharge if dropped. IIRC, Ruger did this change over in the early 1970's.

Charles.  

Quoted: The Old Models have the traditional hammer and firing pin resting on a loaded chamber if you carry and full 6 rounds in the cylinder. This is a no-no as some pistols have discharged when dropped on the hammer, So the traditional solution was to carry only five rounds in the cylinder and let the hammer rest on an empty chamber. The New Model uses a trasfer bar system that allows the cylinder to carry a full six rounds and for all chambers to be full. The transfer bar keeps the hammer and firing pin off of the loaded chamber until the trigger is fully pulled to the rear. So the gun will not discharge if dropped. IIRC, Ruger did this change over in the early 1970's. Charles.

Thank you! I thought the "New Model" was something new to the market like the new smaller Vaquero. So is there any strength difference between the 2?

The transfer bar safety came out in late 72/early 73 so the last three screw Old Models made are over 30 years old.  Can they still fire factory loaded ammo?  Yes, within limitations.  I would hesitate to fire anything over 240g in an OM.  Industry advances during that time frame in metallurgy have made firearms in general better or "stonger" if you prefer.

The SBH 1959 thru 1973, evolved from the 44 BH (Flat Top) 1956 thru 1962, in 1974 the SBH became the New Model SBH. (confused yet ?)
The SBH was a "finer" gun with the chambers recessed for the case rim, beautiful blueing, and very nice fit and finish. The New Model SBH lost the recessed cylinder, lost the beautiful blueing a few years after introduction, and loses a little more each year in regards to fit and finish. However the New Model SBH with it's Transfer Bar and a few other personal changes is still the one others are judged by.
I have used the same load for a very long time in all three which is a 320 cast at 1350 fps in a 7.5" Super, it can go faster but I see no need to do so.