Need load data for 405 gr 45-70 using RE 10x

[Bayou Big Bore]

I am looking for load data for my Rossi Rio Grande 45-70 using 405 gr cast flat point and RE 10x. I have emailed Alliant for help and they replied " I don't see any data in the Lee and Lyman load manuals for that combination", Really? Don't they do their own load testing?

[Tatume]

Alliant offers Reloader-10 data for 400 grain jacketed bullets in the 45-70. You can reduce the load by 10% and work up using cast bullets.

http://www.alliantpowder.com/