Does anyone use the .22 Caliber round in wartime?

Huh.

I’da thunk you’d want a small round that would make as little a pop as possible so as not to bring attention to yourself.

I have one of these. If I had to shoot bunnies and squirrels to live, I’d starve pretty quickly. Accuracy is not its strong suit.

It is cute, though.

From the Wikipedia article:

As for why soldiers don’t use .22 LR, F=MV. 5.56mm NATO/.223 isn’t a much bigger bullet than .22LR, but it’s trucking along at three times the speed. Conversely, the ol’ .45ACP moves at about the same speed as .22LR, but it’s almost six times the weight.

Taken to the full extreme, your average major-caliber pistol bullet (9mm/.40/.45) has about the same kinetic energy as a Major League fastball. The only difference is the baseball doesn’t penetrate. As a corollary, having your Kevlar vest stop a bullet feels like getting beaned by Nolan Ryan – it probably won’t kill you, but it’ll sure as hell ruin your day and most likely break a couple of ribs.
As has been said, it’s used as an assassin’s weapon by the military units that don’t officially exist. Good for silently taking out sentries and the like. Shove a suppressed .22LR pistol in the little hollow behind a guy’s earlobe, it sounds like a muffled sneeze, and the target drops like a sack of potatoes. Cut a guy’s throat like in the movies, and you’d be surprised how loud he can gurgle while drowning in his own blood, and he’ll probably manage to hold down the trigger of his AK and dump the entire magazine in his dying twitches.

Or you could end up like the Navy SEAL my dad met in Vietnam who tried to do the cover mouth/slit throat thing and missed – dude had a scar from elbow to wrist. (My dad was Army and used the .22 to the brainstem, which is where I get this info.)