This is my next project, a 444 Belted.
My test rifle is a Savage Axis, it has had many barrels.
One nice thing is that the Axis is a long action that can use a short action mag.[3"] with a few extra parts.
Chamber can be reamed with a standard reamer.
Loaded with standard dies.
Al you need is a guided drill bushing. [12mm]
And a lathe to final trim the belt.