Hi all. I recently came into a box of Sierra 300 GR .45-70 HP (#8900) that I'd like to load for my 1895G. I only have (and can find) AA 1680 powder at the moment and I can't find any load data beyond the Barnes specs. I spoke to a Sierra tech and he was stumped. He was surprised they had no data on this powder even though they had data on even faster burning powders. I'm not comfortable just transferring the load data from the Barnes to Sierras without a little more guidance. I'm not looking to blow doors down with these loads--something in mid-range velocities would be great. I also have some lead-cast 300 GR from TopBrass-Inc.com that I'd like to load with this powder if possible--at least until I can find some of the more commonly used powders. New to the community and reloading so any advice is appreciated! Many thanks.