I can find reloading information for bullets weighing 300 plus grains and 500 grains in my Hornady manual. Do you have information regarding 405 grain jacket bullets and or any information regarding cast bullets.
Alliant and Western both have limited data on their websites. I don't have my copy of Lyman's cast bullet handbook handy, but they may have data on cast bullets. The 400 grain cast bullet Lyman makes for the leverguns should work well in the Lott. I suspect recoil is going to be the limiting factor in all of this. In the old days we would interpolate the data for a bullet weight between 2 other weights. In other words, split the difference between the 300 and 500 grain data. I would start with the 500 data and work up from there with the 400 grain bullet until you reach a point where the recoil indicates a good stopping point or the chronograph says you have arrived. Certainly, one could look at 458 Winchester loads to get an idea of a good starting place. Bob!! Ouch!!!!!!!!!!!!!! :mrgreen: