Originally Posted by redscho
When reloading pistol ammuntion does it matter the type of bullet as long as they are the same weight. Example, Can I use the same loading data for a 125 gr Lead Round Nose as I can for a 125 gr Full Metal Jacket? I know that loading lead one should stay under 1000 fps.
You can use low end jacketed data with cast. But as in all things reloading, you need to use caution. Cast & jacketed data tend to overlap all other things being equal. Stay away from heavier loads if you're just "Guesstimating."
Another option I've used on occasion is to use the "next size up" cast data. For instance, if you know that 3.5 gr to 5.5 gr of XYZ powder is safe with a 180 gr cast bullet, then you can be pretty comfortable in knowing that your 170 gr bullet should be safe within those limits. You have now at least got a sensible starting point from which to work. Though in this example, I'd probably start with say, 3.8 gr, just to avoid being too light.
If you like to mess with cast bullets a lot, hunt down a copy of the Lyman Cast Bullet handbook 4th edition. It's worth every cent.
As mentioned previously, the Lee Modern Reloading 2nd Edition is a helpful source. It's a compilation of data from other sources, so detail is a bit thin and may also be a bit dated, so I prefer to cross reference data from other sources as much as possible. But it's rare that you can't find something in it for what you're loading. It's also cheap.