Okay, hear me out. . .
What concerns me is a way of thinking that excludes other possible explanations that don't involve some kind of conspiracy, such as powder X must not work well with cartridge/bullet Y, and that's why it isn't listed in so-and-so's manual. I see this a lot on forums. Why? I don't know. I suppose people come up with an explanation that could make sense, and they run with it, without weighing other, perhaps more rational and simple explanations.
Argument #1. There are at least 60 powders that work in handguns. Testing them takes time and money, so it's reasonable to think that manufacturers are not going to test them all for every handgun round they have data for.
There might also be an argument made for how many different powders they might test for a cartridge. Not everyone handloads 380. They might think, well, we tested 6 powders, that's enough. Case in point, Hornady has data for the 38 Automatic, and few folks are loading this caliber. So they have data for 3 bullet weights (110, 115, 124/5), and at most 4 powders. That's probably good enough, at least to their way of thinking. But lots of people load for 9mm, and they have 5 bullet weights (90, 100, 115, 124/5, 147), and 16 powder for just the 115 grain bullets. But even 16 powders is a far cry from 60.
Argument #2. The absence of a powder in a manual for a cartridge/bullet does not mean that powder doesn't work well with that cartridge/bullet.
For example, let's take Vit N310 and 185 grain JHP bullets in the 45 Auto. This is a well known match winning combination. People have known about it for decades. (https://
www.ssusa.org/articles/2016/4/07/usmc-match-45-load/) It has low recoil and superb accuracy. This is not a secret. It is well known on the Bullseye website (
https://www.bullseyeforum.net/) as a great combination. It's often thought of as the Gold Standard (according to some bullseye shooters). Other articles have included it as a powder of choice for super-accurate 45 ammo. (
https://www.shootingtimes.com/editorial/loads-for-the-bullseye-shooter/99418)
You would think that manuals would have this powder listed with their 185 grain bullets. Right? Let's see how many list this powder and bullet combination. Lyman? Speer? Nosler? Hornady? Sierra? Not a single one of them have it in their data. NONE. Why not? Ask them.
So, I do have issues with any claim that says a powder/bullet/caliber combination must not be good simply because it's not listed in a manual. Why? Because it's an assumption based on zero data. But some people make that assumption anyway.
I've asked powder/bullet makers about why some powders aren't included in their load data. Answers have included:
1. We never tried it.
2. We feels it's inefficient - something you have already mentioned, Unclenick.
3. We changed our policy about recommending powders that require extreme compression.
But most of the response have simply been that they never tried it. Not having tried it does not translate into it not being a good powder. As I said, with at least 60 powders that can be used for handgun loads, you have to stop somewhere. And in some cases, like N310 and 185 gr JHP bullets in the 45, they have left out one of the very best combinations known to shooters.
I hope this explains where I'm coming from.