Another point to consider, different bullet types from different manufacturers may have different "sweet spot" for accuracy depending on the pistol, barrel length, powder, charge and OAL (and even the shooter).
So different shooters may end up experiencing differing results and varying accuracy?
While I have been doing comparison load tests for different powders (Bullseye, Promo, Green Dot, W231, HP38, WSF) and different bullet types (Winchester FMJ, Montana Gold FMJ, Rainier Plated, Berry's Plated, 24 BHN lead, MBC 18 BHN lead - I got Moly coated, but I am leaving them out for now), I have found each bullet type with specific "sweet spot" for accuracy at different charges.
So, simply using a designated X grain of powder at X OAL for comparison may give accuracy advantage to one bullet over another. I think this is why we may have different THR members saying, "Rainier is accurate over Berry's" "No, Berry's accurate over Rainier"
For 40S&W, I got additional Montana Gold JHP in 165 gr and another plated in 165 gr TCFP (I do not believe it is Rainer) coming from longdayjake so I will add those to the comparison pot too.
It is for this very reason why I run the full multiple charge test loads for each bullet weight at specified OAL (latest example for 180 gr 40 S&W - 3.5, 3.8, 4.1, 4.4, 4.8 of Green Dot at 1.125") to identify the "sweet spot".
Of course, I am primarily shooting these out of G22/G27. Heck, I may get entirely different results if I used another pistol.
FYI, at the last range test, I got the smallest shot group of 1" at 15 yards with 180 gr Rainier plated out of the G27 - I will be duplicating the load using Berry's to compare. This is smaller than what I usually can get with Montana Gold FMJ.