Well done, Antonio
A vertical mill and a lathe will work.
Mill what you can then use the mill as a manually operated vertical shaper to square up the corners.
About .003" per stroke and much quicker than setting up a shaper.
Technique developed by Harry Eales and works very well.
Made several actions from stock (Ballard, Walker, Hepburn) using the technique.
Set-up takes most of the time, so stock is about as easy as castings.
Chuck