Hi,
I am in process to get a sizing dies, 2 or 3 steps, to size down .375 bullets to .366.
In my 9,3x62 I have used some 235 Speer, 250 Sierra and 270 Hornady Spire point a friend of mine sized down with a one step die. He told me he need a lot of force to do this, specially with the Sierra 250 grs, being his jacket twice as thick as the Speer and Hornady ones!
They grouped very well and behave as a stronger bullet than in the 375 H&H at full velocities, 150 to 200 f/s higher than in the 9,3x62.
I have 200 Hornady 225 grs .375" bullets, now discontinued, made for the 376 Steyr. Will be my practice or medium game bullets for the 9,3, a good match for the 220 grs monometalic FOX classic I have.