Much like Baldhunter, I did some back to back tests with one lot of AA4350 compared to Shooters World 4350, 3 different lots of IMR, 3 lots of Hodgdon, & their long defunct Scot 4351 counterpart. Using a 22-250 Ackley with 53s, a 7x57 with 150s, a 338-06 Ackley with 200s, & a 358 Norma Mag with 250s to get a feel for different capacity cases & different expansion ratios. The lot of A4350 I had was a tad faster than the Shooter's World, which was slower than a can of IMR 4831 I have on the shelf. The Accurate powder was notably slower than all lots of IMR, Hodgdon, & Scot, which also showed considerable differences, even among like brands. I couldn't get enough of the S/W or Acc. powder into the 22-250 Imp. case to be useful. There was over 400fps between it & the "good" lots of H, IMR, & Scot. There was close to 300fps difference in 7x57, 220fps in the 338-06 Imp., & 316fps in the 358 Norma.
I've read other people's testing that disagrees with mine & has AA4350 up there with the others. I think the only "rule" that can be made for the 4350s is that there are grossly different burn rates even between lots of the same manufacturer, although Shooter's World seems to be unrivaled as the slowest.
Like most other powder, once above starting loads pressure, there's not much soot. The spark plugs in all loads were WLRs except the 358 Norma which used Fed 215s.
