Hi maral

Sorry I did not get back with measurements of my Type A Mauser barrel as I promised in my earlier post, I have been away a bit over the last few weeks and lost track of this discussion.

Just for comparison here are the measurements from my 404 barrel:

A: 1.25"
B: 1.33"
C: 1.03"
D: 0.67"
E: 24.0"

Not very different to what you have decided except you are going for a longer measurement for B.

Best wishes for your 404 build.