I shoot NRA PPC. I've found LongShot to be the most accurate powder through my S&W Performance CTR semi-autos with cast bullets. I've shot some national record tying scores with cast bullets (perfect scores).
My load is 120-125gr cast bullet over 5.2gr of LongShot. Gets 1170fps from 4" gun, 1200fps from 5", and 1240fps from 6" gun (PPC-9 "Limited"). However, I'm now using a Lee 105gr SWC over 5.2gr from the 4"gun and 5.5gr from the 6" gun (better slide function w/very heavy slide/gun).
The cast bullets actually out-shoot most of the plated/jacketed bullets on the market. Go figure!!!
I've only shot a few .40S&W loads w/longshot. Most were 12yrs ago or so. I wasn't able to get the advertised velocities, but results with accuracy was good.
I haven't tried it in .45acp as my .45 loads are about accuracy/target loads. Other powders are more economical...
However, with the .45colt (aka .45LongColt), I've found the LongShot really shines with cast bullets, just like the 9mm.
I'm using 10.8gr through a "Lipsey's Special" Ruger "New Model" BlackHawk. It gets 1,040fps w/270gr RCBS "SA" mould (mine casts to 275gr). Accuracy is about 1.5" at 25yds from bench/sandbags. 9.5gr with a 255 FRN (Lee) is equally accurate and gets 855fps to roughly duplicate factory LFN ammo. But, the Lee has a MUCH larger meplat.
I'm using 10.8 because the next larger powder measure cavity throws 11.5gr and gets over 1100fps and is probably too much for long term shooting from my "New Vaquero" size/weight cylinder (.357mag sized cylinder, not larger .44mag sized cylinder).
I now prefer LongShot to Unique, which LS roughly duplicates....
Not to mention that I first bought the LongShot to load 12ga Duck loads, and have worked up buck-shot loads for my 20ga shotguns using LongShot. BTW, I just finished off my second 8lb keg of the stuff. "Note" to self; reorder more....