Originally Posted by Kain
I was a bit dubious to the difference between these two rounds as when placed side-by-side they're not all that different, only about a mm or two. But on my last range outting, I packed 50 rounds of 38 spl and 50 rounds of 357 for my GP100. I really noticed the difference when I loaded 3 38s and 3 357s in the chamber, spun it and snapped the wheel closed and fired without knowing what was chambered. When I rotated from the 357 to the 38s I thought the gun had misfired.
The length of modern cartridges is more about reducing the chance of chambering a mag load in a non mag gun than it is related to horsepower.