I am new to handgun loading. I have probably loaded and shot well over 250K of trap loads, but not much metallic. I'm looking for info on 38-40 and 40 S&W. There is a bunch of 40 S&W data out there so that isn't an issue, 38-40 is something else. I will be using a New Model Vaquero, so blackpowder is not the data I'm looking for. Here is my dilemma, 38-40 has data for 170 and 180 sometimes 200 gr bullets. Most of what I find in lead bullets is 5 to 10 gr under that. Can you use the same data with Unique/Universal/2400 or TrailBoss but with a lesser weight bullet ? By lesser weight I mean 5 to 10 gr less. Thanks in advance for any guidance you can provide.