HWD
These guns are built very close to original Colt SAA specifications. Very slightly thicker and longer cylinders, but not nearly as much so as a Ruger. The flat top target versions frame looks similar to a Colt New Frontier.
Point is any Colt SAA or New Frontier should be shot with loads not exceeding those rec comended for Colts in the various loading manuals. Factory .44 Specials and 45 Long Colts are loaded on the light side out of respect for some of the weak double action / black powder frame guns that are out there.
That being said, with modern production SAA's, it is generally accepted that a 250 grain lead bullet at 1000 fps is a realistic maximum. The old 45 LC black powder load was a 255 grain lead slug at about 900 fps.
A modern SAA like the USFA can be safely loaded a little hotter still, Elmer Keith did it with Colts in the 20's and 30's, but it is HARD on the gun, and any time you load to the edge, you are taking a chance. If you want maximum velocity, the Rugers are the way to go.
My usual load in both my USFA SAA 44 spec., and my 2nd generation Colt SAA 44 spec. is a 250 grain Keith bullet at about 900 - 950 fps. Same with my Colt New Frontier in 45 LC. Enough power for about anything. Often I load down to about 750 fps with the same bullet for plinking.
Larry