amadeus76--

Having worked on over 50 M1903A3 Springfield rifles over the years (since 1972) as a gunsmith I have found that the rear part of the receivers have a very hard surface. This hard surface is a common feature more to the Remington made actions then the Smith Corona ones. Most of the drilling and tapping that I performed on the M1903A3 as a gunsmith involved scope mounts and Redfield match rear sights and bases. The ordinary carbon steel taps will not work even if you drill the starter hole with a tungsten carbide drill bit. You have to use a tungsten carbide tap to thread the hole or holes. The receiver being from a drill rifle should be tested to ensure it will come apart on you.

Cheers

--fjruple