Cartridge designations decoded

30-06, 7.62x54r, .38 special, what does it all mean?  Well, that can be quite confusing.  Basically, you have to look at each cartridge individually.  There is no one set standard for all cartridges.  Some were named in the days of black powder, some by NATO, and others by foreign governments.  And yes, some cartridges are known by more than one name.  I will break down a few different cartridges and try to explain what all that stuff means.

30-06 is a very common rifle cartridge that was once the standard for the US military.  The “30” refers for 30 caliber.  The bullet is 30 caliber.  Specifically .308 diameter.  The “06” refers to the year that it was adopted, 1906.  Pretty simple.

30-30 Winchester is also a common rifle cartridge.  The “30” again refers to the 30 caliber bullet, but this time the second number refers to the powder charge.  The 30-30 was originally designed for black powder.  So, it would have been loaded with 30 grains of black powder.  The Winchester part just means that it was Winchester that introduced the cartridge to the commercial market.

Some can be super misleading.  Take the .38 Special and the .380 auto.  You might assume that they are both .38 caliber bullets.  You would be wrong.  The .38 special takes a .357 diameter bullet.  The .380 takes a .355.  Stupid right? 

Then there are the ones with 2 names.  The .308 Winchester is also known by the Nato designation 7.62x51.  It’s the same thing really.  Nato spec rounds may me loaded to higher pressures, but the brass case is really the same thing.  .223 Remington and 5.56 Nato are another example.  Remington introduced the round to the public as the .223 while the military was loading theirs as 5.56.  Again, 5.56 may be loaded to different specs and the case walls might be slightly thicker in military brass, but the overall package is the same.