The reloadammo.com site load data is one I have previously referenced successfully, however...
Although the info for 45 Colt specifically indicates that HP38 & WIN 231 powders are identical, the load data for the subject of this thread, a 200gr SWC obviously differs with 8.3gr of 231 producing a "998 fps MAX LOAD" and 8.0 gr HP38 a "1002 fps maximum". There's also an additional(?) 9.0 gr HP38 load @ 882 fps?
Just a comment: not everything that is "published" is necessarily accurate.
Cheers!
P.S. With the given caveat to start at minus 10% none of this data seems at all dangerous. Working up is always a good practice.
VERY good point. Different sources will give different load data for a given powder.
That is one of the main reasons I always go to the powder manufacturer's website, whenever possible.
Below is a screenshot of the Hodgdon load data for 200gr LRN using HP-38, which as you noted, and everyone agrees, is the same powder as W231.
If you get your load data directly from the powder manufacturer, that is where you will be most likely to get consistent data.
The W231 data I posted earlier and the HP38 data on the Hodgdon website are identical. Since the two powders are actually the exact same product, simply packaged differently, that is what would be expected.
Over the years I have found a few discrepancies, even when looking at powder manufacturer's published data. But that is pretty rare.
If you go to OTHER sources, like reloads.com you will see a lot more inconsistent data.
That isn't to say that those other sources publish BAD reloading data. I'm just saying that I tend to trust data that comes directly from "the horse's mouth" (the powder manufacturers) more than any other source. Generally speaking, these are the most rigorously tested loads.
Load recipes from other sources MAY be perfectly safe. But I tend to trust the data from the folks who actually manufacture the reloading components more than other sources.
But that's just me, and YMMV.