Rimfire and Centerfire
 

I'm only starting to recognize these now and I wanted to know the difference. Anyone know?

Rim fire has a ring around the rim of the brass (cartridge) that detonates the charge. When I say around the brass, I mean around the rim of the rear of the shell. The end the bullet is not on. Rim fire shells are not reloadable. They are cheap.

Centerfire cartridges have a primer in the center (of the ass of the shell) that is struck by the firing pin. The primer goes "bang" then the charge goes bang. The used primer can be pulled out, a new one put in, and the brass can be reloaded and used again.


So, centerfire has that little plug in its ass, rimfire does not.

Examples:

A .22 is rimfire.

A .38 is centerfire.

I only know of a few, small, calibers that are rimfire. I've personally never seen a shell other than a .22 that WAS rimfire. But then, I haven't seen THAT many different caliber shells.

Generally, rimfire is used in small cartridges like .22 lr (which are too small for centerfire to be practical), while centerfire is used in the larger cartridges.

The reasons for this are simple.
1. You can't reload rimfire cartridges since it is impossible to replace the primer.

2. In larger calibers, centerfire cartridges are far more accurate and reliable than rimfire cartridges. This is because the primer in a rimfire cartridge starts burning at one place on the outside of the case and burns around the cartridge, which doesn't consistently ignite the powder in the same way each time. Centerfire primers blow out from the center of the cartridge and ignite the powder in a very uniform way which increases accuracy.

So centerfire cartridges are cheaper, more accurate, and more reliable than their rimfire counterparts.

The only rimfire cartridges i have ever seen come in .22 caliber and there is one 7.62mm rimfire cartridge. There may be variations of the .22 that are also rim (.220,.223), but most .22 variations are centerfire. The new .17HMR is centerfire also, smallest rifle caliber thats widely available.