I think some of our accepted "this powder is just like that one" verses are really reloading misconceptions. Accurate No. 9 and Shooters World Heavy Pistol/Lovex D037-02 are "comparable," not the same and definitely neither one is the same as Ramshot Enforcer/Accurate 4100 or even really comparable in a practical sense. Now, thing is, if we follow the rule of road - "when changing any major component, always drop back to a listed starting load and work up..." - then hoe comparable or near identical gets to be almost unimportant. But I've seen way too many questions recently about swapping powders and starting with people's "pet" loads that exceed published maximums. Its a misconception that different powders - even when they're "the same powder" - are interchangeable. Or am I picking nits, now?
Lovex D037.02 and Heavy Pistol is the same powder. Shooter's world get's it in bulk containers labeled D037.02, takes it out, and packages it as Heavy Pistol for their consumer cannister powder business. If you work with SW's OEM side, you won't get these powders labled with the SW names....you'll get bulk Lovex names. In fact, they will make a point of this...if you're a retailer, you buy consumer labeled cannisters, if you are an OEM, you get Lovex labeled jugs. This is also the same powder that ***was*** AA#9 prior to the Western Powders contract moving to General Dynamics. Certainly there is some drift in the ensuing years, no different that if you compare a lot from a decade ago to a lot today of any brand....and when you look at a current batch AA#9 and Heavy Pistol, you'll see a different color......but GD makes it to the same spec as Lovex makes it......and the load data works up exactly the same in my guns. If you are willing to buy enough, you can also buy most of the AA powders direct from GD, and they will be called something else entirely.
When talking powder similarities, there are two considerations......is the specification the same used to produce it...IE, AA9, and SW Heavy Pistol are made to the same specification by two different companies and the load data is the same.......and secondly, can it be mixed (tailed). These aren't always the same answer.....a powder can be the same or very close spec, but not tailable, or not tailable by anyone sane I should add. I personally would NEVER tail AA9 and Heavy Pistol. They are the same spec.....but different plants, countries, QA process, storage process, different sources of nitro cellulose, etc, they do share the same load data however. I would also confirm the same load behaved as expected, if I had batches of both ( I don't, I see no reason to pay 2x more for the same thing). Win296 and H110 as a another example, ARE the same powder, not two different powders made to the same spec, but the same powder, made in the same plant, by the same people, on the same equipment, using the same ingredients...and are completely tailable, and regularly tailed by many many shooters and have been for many years, and Hodgdon support will tell you they are the same powder as well. So if you don't tail powders, then it doesn't really matter......but if you tail H110 regularly......there is no reason at all not to tail W296 with it, if you have cannisters of both.
I'll also add, if you work up a new load because you used up the 10lb Jug of Unique you bought 10 years ago, and you just bought another 10lb jug you'll use over the next 10 years......then by all means, completely redo your loads switching from AA2 to Cleanshot. If however, you crack that new jug and load up a batch using your tried and trued load you've been using for a decade.....then you might as well use the same load data from a jug of AA2 that you've been using for Cleanshot....because your variance is going to be about the same..spec is spec.....whether it's the same brand 10 years later, or the same spec made in two places. Sure, we all know guys who rework an entire load for a new lot of powder, and if you load low volume, or you are always on that Elmer Keith edge, then that's what you do.......but a high volume loader, using standard loads.....he ain't gonna do that. He'll shot a sample batch, and verify it's the same quality as his past ammo, and shooting to the same POI, with the same velocities and performance (if he's smart, he's always doing that all the time), but he's not going to start over.
