Springfield Rifle 1903: Caliber & History Explained

Question
Hi I was just wondering about the 03 springfield rifle chambered in 30-06 I know that 06 stands for the year the cartrage was introduced, and 03 is the year the rifle was introduced. what was the rifle chamberd for for the 3 years there. Asked a lot of people this and heard alot of responses.

Answer
A round called 30-03.
It was not powerfull during the fighting In Phil. Is.
A new more powerful round was developed in 1906.
All rifled chambered for 30-03 were converted to 30-06.

btw
The secound number standing the year is unique to this situation. 30-30 is 30 caliber, 30 grains of powder