In loading manuals, there is usually a number called a ballistic coefficient.
That number is used to compare the flight characteristics of one bullet to another, and is, in my opinion, the best way to compare one bullet to another. (Assuming the material, lead, jacketed or plated is the same.)
Smaller companies (like a lot of the one or two man companies that produce lead bullets) frequently don't produce either data or manuals, and then the best way (again in my opinion) is to measure the weight, diameter and length of the bullets, and keep styles and type (jacketed, plated, lead) the same.
For .45 ACP, there's not going to be any problem finding data for a 230 grain JRN-- it's probably the most common round loaded. The other super common bullet would be the semi-wadcutter. (SWC). You can find all sorts of listings for those in 200 grain, in plated, jacketed and lead.
The last method I would use would be to substitute styles. I might do it when I've made a hard search, but so far, I've always managed to find the same style-type-weight, particularly in .45 ACP.
Sometime you might need to buy a different manual, and if, for instance, you're loading Hornady bullets, then the Hornady manual is guaranteed to list exactly the bullet you're loading.
Another approach is to buy one of the big manuals (Hornady, Speer, Federal) and then buy exactly the right components to match one of their listings. That's probably the most conservative approach, but in reloading, conservative habits are good habits in my book.
And no, I said that changing brands of primers or changing brands of brass changes both pressure and velocity.
"Huh?" --Jammer Six, 1998