So it is true that Unique is dirty?
Yes, it's a slower burn rate powder. People use it in 38 Special only because it's "fluffy" (i.e. not very dense) and occupies a huge amount of physical volume. Thus it fills revolver cases very well. (Most revolver cases were designed for Black Powder which is
very voluminous.)
38 Spcl and 45APC want a fast powder (like AA No.2) due to the very low cartridge chamber pressure, which is around 18,000psi. 9mm Luger, which is up around 33,000psi, burns it much better, but it's still too slow.
Think of gun powder as a fuel. Whenever you burn fuel
inefficiently, you end up with 1. unburned fuel (with a solid fuel that equals "trash"), and 2. lots of soot. If you've ever had a car, motorcycle or lawn mower that had a stuck choke, then you've seen the black smoky exhaust and black, sooty spark plugs. Same thing with a kerosene lantern. If the wick isn't correct, then you get lots of soot and not much light.
So yes, Unique is trashy and sooty because it's not being burned
efficiently in 9mm, 38Spcl and 45ACP. That doesn't mean it's a "bad" powder. It might be great in 10Auto or 44Mag where it's pushing a 200-300gr bullet. So it's simply wrong for the cartridge application. In decades gone by (the 1970's & 80's),
Bullseye and
Unique were about the only pistol powders, so people had to "make due", but that is NOT the case now. There are a dozen or more
excellent powders now available for 9mm. But some internet rumors and bad habits simply won't die.
When you say meter well, do you mean measuring the powder charge? Sorry for the silly questions.
No such thing as "silly questions". But this was already answered above...
Unique and Bullseye are both over 125 years old. They are "standards", but there are powders the same burn rate that are simply much easier to work with. Unique is OK in 38, but actually a tad too slow for 9mm. It also has coarse crystals that are known to "clump" inside the powder measure and not meter accurately. Bullseye does much better as a dual-use powder, but you can easily beat their handling and performance with more modern offerings.
True, since about year 2000, Unique got a more uniform powder grind that fixed
some of the issues... but it will clump and remains far too slow of a burn rate to be effective in 9mm with 115 and 124gr bullets. It might start to have application in 147gr loads, but speedy loading for 147gr accounts for about 3% of all 9mm shooting. Unique doesn't have a flash suppressant, so why you'd want to use it in SD loads with 147gr when N340 and BE-86 are available is absolutely beyond comprehension.
These "modern powders" were pushed by the popularity of pistol competitions starting in the 1990's. People simply wanted something better, that burned efficiently so that their pistols wouldn't jam with trash after 80 rounds, that could be measured accurately round-after-round, and that would burn efficiently so that the least amount of powder could be used to do the job.
Do I own a can of Unique ? Why, yes. Do I use Unique for anything ? No. In fact my can is from ~1993, is the old paper can and marked "Hercules". I doubt the can has even been opened in the last 10 years !!
