Hello. I’m about to make a very small black powder derringer in cal .41. I want to make the barrel very short, and I read that derringer-barrels could be as short as 1.5” back in the days. But such a short barrel will lose alot velocity, especially with black powder that burns relatively slow. How much velocity losses will a too short barrel generate step by step? For example, will a 2.5” barrel make a big difference compared to a 3”? Is there any optimal barrel length in order to keep it as short as possible but without too much velocity loss? What was the most common barrel length of BP-derringers back in the days as reference?