Groo here
Way back when ,,,,,, the 5in was the gold standard [some say 6in]
When cops started to drive cars the barrel became too long.
You will note that the original short 357 was a 3 1/2 in,
but that was with a short cylinder.
now ,with the long cylinder , a 3in is about the same size.
The 3 and 5 in are about the best for long and short use
and get about the best FPS per inch.