figuring I could use the expander from the 7.65x53 in the 30/06 case and some 311 or 312 bullets?

What thousands of others have done with their 1909's that were simply rechambered to .30-06. Just make sure the chamber neck is not too tight on a case with .311" bullet seated..

Been there, done that on two different 09's. Worked perfect. Like Z1R said, just check that the neck is not too tight, I bet its not. Those were not the best rechambering jobs, but both shot really well.