By the end of the 19th century, the .30 Krag was the standard cartridge for the US Army. However the case of this cartridge had limited capacity for powder. In 1901 development on a new cartridge started which resulted in the 30-01 cartridge. This was merely a long version of the .30 Krag cartridge with the rim cut off and an extractor groove added. This cartridge is also known as the "thick Rim cartridge".

The 30-01 cartridge was loaded with a 220 grain round-nosed bullet with cupro-nickel jacket.

The 30-01 cartridge was replaced by the 30-03 cartridge. The only change was that the thick rim was removed. The cartridge was still loaded with the 220 grain bullet.

With the development of pointed bullets in the early 1900's, the case of the 30-06 was cut by one tenth of an Inch. On October 15, 1906 the 30-06 cartridge was introduced. The cartridge was loaded with a 150 grain bullet.

From left to right: .30 KRAG, .30-01 (note the thick rim), .30-03, .30-06