I have a Birmingham made “colonial grade” dr, signed by Alexander Robertson & son, Wick in north
Scotland, in .500-450 No.1 BPE. Steel barrels, shortened due to severe rust damage at the muzzles only and reregulated
by me. I have developed two “Nitro for Black” loads over the years. Cases formed from Horneber .500
3” NE brass. Federal Magnum large rifle primers.
350 gr Hornady, 70 gr VV N140, packing foam filler, for 1850 fps iv.
300 gr Barnes (hp for .45-70), 75 gr VV N140, foam filler, for 1900 fps iv.
Shot red deer, wild boar, roe deer and even a fox with these loads. One quirk: The .500-450 No1 had a slightly thicker rim than the available .500 base cases. You may have to find a way to make them headspace correctly. I modified the extractor of my rifle.