Odds are you have fired a cap gun once or twice in your life. Most likely, if you are reading this, you have fired a 22 once or twice in your life. But the thing is, have you ever fired a 22 that sounds like a cap gun? Well if not, the 22CB may be something to look into.
22 CB Cap (short for "conical ball cap") is a series of very small 22-caliber rimfire cartridges that have been around since 1888. On average, full-powered rounds for the caliber are typically 29-grains of bullet that travel at 700-feet per second. They are smaller than 22LR (40gr, 1100-fps), smaller than 22-Long (29gr, 1000fps), and smaller than even 22-Shorts (29gr, 800fps). They are however larger and more powerful then 22BB (18gr, 750fps), the Mexican-made Aquila Colibris (20 gr, 375fps) and Super Colibris (20gr, 450 fps) rounds. They have been kept around for almost 150-years for their versatility. They allow clean and efficient hunting and pest control (better than the Colibris and 22BB) but without the loud cracking sound and extreme range of the larger 22L/LR round.
The .22 CB has long been used as a so-called 'gallery' round. In the old days (before lots of liability lawsuits) amusement parks offered shooting galleries where would-be marksmen would pop off rimfire zingers at small targets in an effort to win cupie dolls and stuffed animals. These rounds were first pioneered by a French inventor by the name of Louis Flobert in the 1840s when he took a rimmed percussion cap and mounted a small lead bullet directly onto it. Today gallery loads are still made for the .22 CB, marked 6mm Florbert. Imported into the US from Germany where they are made by RWS, they run about $35 for a hundred. There has long been a practice of personal basement shooting ranges with a backstop of several sandbags and low-powered .22CBs. To avoid possible ricochets it is advisable to make a cave of sandbags and place the target to the back of said enclosure. Of course, follow all safe range procedures and Firearms Talk assumes no liability et al.
Urban pest control
Hundreds if not thousands of small furry creatures have been filled by this humble little round. In a revolver, the .22CB does not generate a lot of power but in a rifle, it will penetrate 1-inch pine planks at 25-yards. A 100-round box of .CCI 22 Short CB costs about $7 CCI, and shoots a 29-grain Round Nose Lead Bullet at 710 fps, delivering some 32 ft. /lbs of energy at the muzzle. At 50 yards through a rifle barrel, it still has 656 fps and is capable of delivering 28 ft. /lbs of energy. This is effective for through-and-through shots on small game such as squirrel, raccoon, and rabbits as well as against pests such as polecats, cotton rats, and mice. These rounds deliver a lot of power for such a tiny little load-- and are much less noisy than a spring-action .177/.22 pellet rifle. This is because the low velocity of the CB doesn't break the sound barrier like your super-fast high performance air rifle pellets.
image from Ballistics by the inch
Most .22 rimfire rifles and revolvers will fire the 22CB, which means you probably have a few guns that are chambered for it lying around right now. Beware that this ballistic pipsqueak may not cycle a semi-auto, but can be hand loaded and ejected. I've never seen one 'stick' but make sure the round has left the chamber when firing a 22CB from a semi-auto rifle the first time and have a good quality cleaning rod on hand just in case.
These rounds make a great (and quiet) survival tool, plinker, or critter getter. A hundred rounds of 22CB will fit inside a small Altoids sized tin for easy storage and carry. If you buy an inexpensive $3 survival tin with a rubber gasket, a hundred rounds or two can fit with room to spare for other small items in long-term prepper storage.
A hundred dollar bill will get you something on the order of 1300-rounds of these bad boys...which if stored properly is a whole lot of shooting fun.