[Travis McGee]

Usually when folks say ".22" they are referring to .22 rimfire, sometimes written .22LR for the most common type, .22 long rifle. They also come in shorts and longs and a few other sizes based on case length, powder, and slug weight in grains and type, round nose, hollow point etc. The most common .22 would be a .22LR firing a 40 grain soft lead round nosed slug at about 1,050 fps out of a typical rifle. The entire cartridge, slug and brass case, is about one inch long. The case is just side enough for the .22 slug to fit, it does not widen out. The primer is in the rim, hence rimfire. Anywhere the striker hits the rim, it fires.

What the sniper is shooting is also generically speaking a ".22 caliber", but it is a centerfire cartridge with a separate primer installed in the bottom of the case. The case expands outwards from the neck in the shape of a bottle to hold much more powder. The M-16 and AR-15s etc typically fire a 50 to 65 grain slug at from 2900 to 3200 fps depending on the load. At these extreme velocities the wounding and killing power is MANY times greater than the 1000 fps .22LR.

There are other ".22 calibers" even larger in case size than the .223 the DC sniper is using, which push rounds up near to 4,000 fps. These are generally used for varmint hunting and target competition.

[Huck]

Thanks.