Check the cast boolits website. Look for 'cat sneeze' loads.
They also have links to some of the old reloading manuals, so that you can check the data .http://www.castpics.net/LoadData/OM/default.html
Lead bullets are the key. I have loaded 30-06 to the recoil where a 8yr old has fun shooting it.
As an example of published data, 120gr cast,7.0gr Red Dot, 1400fps. You can go lower, but when you go really low, check them in the rifle they will be used in so that they will not stick in the barrel, then increase .5grain. Some folks go as far as using a round ball instead of a bullet.