Not true, generally only high powered rifle bullet's are super sonic.
That's not true, my old .22 fired supersonic bullets, and that round was also used in the pistol I was given when I first worked as a bank teller. There are some modern pistol rounds a little under the speed of sound, but few, and most are designed for older ammunition types like the .36 S&W and ACP (Automatic Colt Pistol) that have been around for over 100 years.
Speed of sound is 1,126 ft/s.
.22 Short Rifle 1,164 ft/s - except those designs as sub-sonic rounds - often used in a lady's pistol
.22 Long rifle 1,200 ft/s and up.
.221 Remington Fireball pistol round 3,791 ft/s
.50 BMG 2,815 ft/s
.45 GAP (Glock Auto Pistol ) 1,152 ft/s
.357 magnum 1,500 ft/s
9 mm parabellum 1,155 ft/s (most other 9mm rounds are faster)
10 mm Auto Pistol 1,551 ft/s
.38 super 1,300 ft/s
.45 magnum 1,472 ft/s
.460 S&W Magnum Revolver 2,200 ft/s
edit to add - I forgot to mention the .44 magnum at 1,550 ft/s