The throat was not widened to D specification, a D 166 just kisses the lands, when seated to mormal OAL, which is 76mm.
My D-Load is 45grn of N140 behinfd the D166 at 76mm and with S&B cases.
All my M28/30, but the 1940 one, get Lapua Match ammo with D47 or handloads with D46 bullet of 185grn, like the CG used back in the 1930s.
This load is also used in two M27 with tight barrels and one early Tikka M91.
I keep records of all my rifles and their barrel dimensions, no matter if they are Mosins, Enfields or Mausers

I have shot the 1938 M28/20 once this week, but my elbow did hurt too much, to produce good groups.
Will repeat the firing, when everything is back to normal.
Chris