AA#9 is my favorite and most accurate powder for .357 Magnum with 158 gr. bullets and is what I use for both revolver and a lever action carbine rifle. I see no issues with flame cutting the top strap unlike Win 296/H110 which has shown flame cutting to some degree in my 44 Mag. Ruger Super Blackhawk. I prefer Hornady 158 XTP's and AA#9 just slightly less than Accurate Arms maximum data. I have found Accurate data to be realistic. Accurate Arms Manual #1 used CCI 500 primers in .357 Mag while later Accurate data tests with CCI 550 magnum primers. I have had best accuracy with the standard primer. Again I think AA's data is "accurate". I have a load with Win 296 for 44 Magnum that shoots so well in my pistol and Winchester 16" Trapper rifle that I just haven't tested AA#9 in anything but 357 Mag. It is too slow for anything but magnum calibers.