I have a forged Ballard with  .357 Maximus  chambered barrel on it.  I shoot black powder breech seated 200 grain bullets in it now.  I would like to shoot smokeless powder it in at about 1450 fps.  Cannot find any mild loads on line for this cartridge that would be safe in a Ballard.  I also plan on breech seating the same bullets as with black powder.  Any help would be appreciated.  Charlie

Thanks I do not have any of those powders I will have to find some.  Charlie

4227 burns a little slower than #9 so, you could start with the same loads and work up. 300MP is even slower burning but, if you want ~1450 fps, you will need a chronograph to insure it. You might go +.5 with the 4227 and +1.0 more with 300MP than I listed with the #9 loads, safely. 

I've shot much hotter than those loads, with GC bullets in my LW both BSed and fixed so, I think you'll be fine pressure wise but, always start low with a new powder. I consider a LW on par with a forged Ballard strength wise.

Let me qualify my statement regarding LW/Ballard strength. 

I consider them equal up to the size of a 30/30 - 32/40 size case head, @ BP pressures, because of the smaller barrel thread size of the LW.