Originally the .357 Magnum was a potent cartridge, loaded with 158 grain lead semi-wadcutter bullets. It was said to be loaded to higher velocities in the 1930s than it is today. I've never chronograhed any.
An older Smith & Wesson forum thread shows some early ammunition and boxes.
http://www.handloads.com/articles/default.asp?id=30 (an article on the subject of the .357 Magnum by the great Skeeter Skelton)
One can't help but wonder if the factory loads leaded like fiends.
I like using either the original 158 grain lead semi-wadcutter bullet or else a 158 grain jacketed soft nose or hollow point when handloading for my .357 Magnum revolvers. Have enjoyed using up to 180 grain bullets on the past. Only personal opinion but I have no use for the 110-125 grain loadings or component bullets and feel the lighter bullets are overrated. Especially the vaunted 125 grain slug which receives entirely too much play in the internet rumor mill for it's performance to be taken at face value. The .357 Magnum is very capable of using heavier bullets than that and to good effect.
I've got a box of Remington 125 grain factory JHPs idling on the shelf, awaiting time to chronograph, just to see what real-world velocities will be. Just got to clear the schedule of other commitments.