.416 Rigby loads with IMR 3031?

Hector, compadre;

What are you looking for in performance? Bullet weight? Velocity? Cast bullet, right, since this is where you're asking the question?

I suspect there are some decent loads for 3031 that would work in your rifle, but I haven't gotten around to this powder yet in my own .416.

Give us some more detail and we'll see if we can help out.

Regards from BruceB (aka Bren Mk1)

dear BruceB
Cast bullet 350 grains with gas check.
Velocity: around 2.000 to 2.300 feets.
Gun: Mahillon pre-war (belgian gun maker)with Mauser action and 26" barrell (five cartridges in the magazine!!!)
Thanks in advance.
Regards.

H. C. Roveda