Re: Barrel Length and Bullet Velocity Ratio
There's very little in this game that's linear, and this is yet another example of that. Velocity gain/loss in re barrel length varies substantially with the barrel lengths we're talking about, the expansion ratio (cartridge capacity), the bullet weight and many other factors which come into play. Bottom line is, it's all over the place, and virtually impossible to say that X increase or decrease in barrel length results in Y velocity change.
Sorry, and I wish there was a simple answer to this one, but the question is a little too broad for a single, concrete answer.