I have .22WMR in a 6.5” Ruger revolver. You can definitely tell the difference from 22LR at that length.
Six inches is probably about the minimum for the .22 magnum to start making a real difference.
Many years ago, a friend and I did some chrono testing with one of those tiny .22 revolvers. I can’t recall if it was a North American Arms or a Freedom Arms but it had a one inch barrel and two cylinders.
To make a long story short, there was only around 3 ft. lbs. difference between the .22 short, LR and magnum in that barrel length. Still technically the magnum had the most power but at an incredible amount of muzzle flash and recoil was pretty bad too. For those tiny revolvers, the .22 short is really the ideal cartridge.