I really need to get myself a 4" revolver in .22 WMR for the heck of it. Anyway, if one is considering rimfire, the boost of speed and flat shooting a bit further out (.22 WMR rifle vs. handgun) is something to consider.
Some old numbers from a few years ago with different guns all in .22 WMR.
Zastava Mini Magnum 16.25" bbl
Hornady VMax 30 grain = 2359, 2287, 2322 fps
Remington 40 grain PSP = 1996, 1880, 1885 fps
Winchester Super X 40 grain
JHP = 1907, 1888, 1875 fps
Ruger Single Six 9.5" bbl
Hornady VMax 30 grain = 1683, 1749, 1711 fps
Remington 40 grain PSP = 1461, 1375, 1383 fps
Winchester Super X 40 grain
JHP = 1403, 1404, 1295 fps
Henry H001M Lever Action 19.25" bbl
Hornady VMax 30 grain = 2393, 2256, 2324 fps
CCI Choot Em 40 grain
JHP = 2035, 2017, 2020 fps
Hornady Critical Defense 45 grain = 1867, 1883, 1801 fps
Keltec PMR 30 4.3" bbl
Hornady VMax 30 grain = 1585, 1572, 1579 fps
CCI Choot Em 40 grain
JHP = 1221, 1251, 1236 fps
Hornady Critical Defense 45 grain = 1195, 1330, 1266 fps