The lowly .22 caliber LR (long rifle) round is becoming a favorite among snipers. Professional assassins (usually thugs working for organized crime) have long favored using .22 caliber (5.56mm) pistols for their work. While not a powerful round, if you shoot someone up close with a .22 caliber pistol several things are noted.
1- The victim is dead if you shoot him in the head, whish is what pros usually aim for (as these guys like to say, "two in the head and you know he's dead.")
2- There is hardly any sound if you use a silencer, and not much even if you don't.
3-A 22 caliber pistol is small, even with a silencer. That makes it easier to conceal, and easier to dispose of.
Then the Russians noted that Chechen snipers were effectively using .22 LR (long rifle, them little bullets kids use to hunt squirrels and rabbits with) weapons. Inside towns and cities, the .22 LR sniper was very effective, especially since the Chechens would improvise a very workable silencer by putting a plastic bottle on the end of the rifle's barrel, with a hole in the bottom of the barrel for the bullet to exit. Using a cheap scope, Chechen snipers were very deadly at ranges of less than a hundred meters. Such ranges were pretty common in built up areas. And since you usually did not hear the shot (to the head or face, of course), you had a hard time finding the shooter. Having suffered from these low tech .22 caliber Chechen snipers for ten years, the Russians have come out with their own professional .22 LR sniper rifle, the SV-99. This is a little heavier (at 8.3 pounds) than your usual .22 LR rifle, but is built for professionals. It has a heavier barrel, a bipod, silencer and scope. It's 39 inches long and can accept five, eight or ten round magazines. There is a compartment in the butt stock for two five round magazines. With the SV-99, at a hundred meters, a skilled shooter can consistently put all rounds in a half inch circle. This is a specialist weapon, most likely used by commandos. But any trained sniper can quickly adapt to using it. And snipers like not being heard.