Guns: Regarding .22 Long Rifle

I was testing out my new CZ magazine springs (they work great BTW - 400 rounds of 9mm downrange with no problems), and in-between firing the trusty P-01, I used my equally trusty Kadet .22 conversion. I must have put a brick's worth of .22 Long Rifle through my Kadet kit in that one range session. I was shooting the most common cartridge in the world - the .22 LR.

There used to be a rich assortment of rimfire calibers, but with the advent of smokeless powder and the correspondingly higher pressures generated, these have all died off, and only the .22 LR remains (well, aside from stuff like .17 HMR and .22 Mag, but they're not nearly as common). You can buy the cheapest .22 LR in $10 bulk packs, known colloquially as "bricks" or "550s" because of their form factor and the 500+ cartridges one can cram into said form factor. There are also match-grade .22 LR loadings available, the kind of stuff Olympic shooters use.

The bulk pack stuff is dirty and nasty compared to modern centerfire ammunition. It's manufactured in huge factories, with less attention paid to consistency or even quality control (you'll probably have more squib .22s than all the other calibers put together). The residues and unburnt crap coming off of the "primer" material (the stuff hanging around in the rim of the cartridge )are not fun to breathe in - sometimes there's literally a cloud of smoke hanging in the air after a magazine's worth of .22 rounds. I was looking at my boogers hours later and they were stained black. Ewwwww.