Surplusrifle.com has a detailed, step by step process. Look for the links on the left side of the page under the Maintenance heading. http://www.surplusrifle.com/03a3/index.asp
which model It is probably best to let a professional, such as a gunsmith, do it. This will minimize the risk of damage.
The Model 1903A3 rifle is base upon the Mauser 98 action but they are not exactly the same.
Springfield, Mass...........................
With the serial number that you have supplied,your Smith-corona model 1903A3 was made in the year 1943.these rifles were only made in the years 1943-1944.If your rifle has a letter C prefix to the serial number,then this indicates that remington also made a model 1903A3 with the same serial number. These were the only 2 manufactures of the 1903A3 rifles.
You can request a manual from the company.
With the serial number that you provided,your Springfield model trapdoor rifle was made by Springfield armory in 1883.
Best to ask a gunsmith for assistance.
yes there is a springfield .303 i have one from 1942 its a springfield rifle with a .303 british barrell
Do not atttempt this. Find a gunsmith.
Ask a gunsmith for help
often it was the 1903 springfield rifle
As fast as you can operate the bolt of the rifle.