I cast .321 150 gr bullets for my 1905 32 WSL (bore-.320), using 32-20 brass (no extractor groove) and 32 SL dies. I expanded the case mouth slightly. With 11.6 gr IMR4227 (slight crimp), each round loaded, fired and ejected perfectly. Accuracy was good for me.
But, the 32-20 cleaned brass would not size down at the neck. The cast bullets dropped right in.
I Beagled the mold, first with one side taped, then both - with both sides taped, the bullets measured .324-.325. Even at that, I could finger press the bullets into the cases. With a slight crimp, those bullets all loaded, fired and ejected perfectly. Accuracy was the same.
I fired off 2 original rounds (162 gr jacketed bullet, cases have an extractor groove). The original cleaned brass sized down perfectly (the brass is thicker than the new 32-20).
Then, I bought a used 32-20 sizing die, sized the cleaned fired brass back to 32-20, then sized in the 32 WSL dies, expanded the mouth to take the .321 bullet and I'm back to where I was.
I have not made a cast of the chamber. The bore is near mint - I don't think it was ever fired much. I did not anneal the brass.
Considering the age of this rifle, is it better to...
Keep sizing down to 32-20, then up to .32 WSL or use the larger diameter Beagled bullet?