Winchester’s new M22 round is quite compelling. It features a 40 grain round nosed lead bullet at a high velocity of 1255 fps. The round has been designed specifically for modern semi-automatic rifles feeding from high capacity magazines (ie. .22 black rifle clones).
For comparison, 40 grain .22 LR bullets are usually loaded for subsonic velocities. High velocity .22 rounds are generally 36 grain bullets being pushed out the muzzle at 1328 ft/s.
The M22 round will go on sale later this year and will be sold exclusively in bulk 1000-round value pack.
UPDATE: It has been pointed out me that other brands, like CCI Mini-Mgas, have 40 grain bullets being pushed at super-sonic speeds. Sorry about the mistake.