One more thing before I go on the the reassembly part, or the "how it shoots" part that usually bores me to tears when I read them.
The Mauser M2 has a fully supported chamber.
The feed ramp is NOT part of the barrel.
Once the round makes its way up the feed ramp and into the chamber, the barrel will move forward until it reaches its stop and the barrel rotates to lock itself to the slide.
At that point, the cartridge is fully supported all around the head.