4 1/2, and $34.12.
Bottom of receiver in front of trigger
The bottom of the barrel, left of center, just in front of the stock.
On the bottom of the receiver, ahead of the carrier cutout, or on the left side of the receiver toward the bottom. sales@countrygunsmith.net
There is a chart at the bottom of this page: http://www.remington.com/magazine/history/m11_5.htm
Your Remington 1903-A3 was made by Remington in 1942.
The phone number of the Remington-Carpenter Township Public Library is: 219-261-2543.
Email Remington with the #. They will get back to you.
Email Remington. They will get back to you.
No such model number listed on Remington's web site.
You will have to call Remington with the serial number.
No such model number in the Remington line
90 protons