I don't quite see it the same way. If I were starting from scratch with the loads/gun, I would definitely see the logic though.
I know it's not 100% scientific, but over the course of several hundred rounds initially in the gun, using the other loads (RN or HP, regular powder charges), I had VERY consistent accuracy.
With the (accidentally) FP bullets loaded over the same powder, but being compressed to the shorter OAL (by the guns' action) I also had excellent accuracy.
Loading to the shorter OAL (1.030), and lower charge (3.9gr), the gun seems to shoot very inconsistently.
Agreed, there are several variables in play, but the 1.030 is somewhat fixed, based on the chamber, and the powder charge is limited unless I hear othwise, or very carefully test some loads with .1 gr difference.
That's what I'm mostly trying to determine, if using the previous combination again it will shoot consistently.
If so, I'll probably stop messing with the XTreme FP bullets I've got and either sell them, load them for my carbine, or if I hear back from Hodgdon's with additional load-data, load them up a bit and see if they produce consistent results.
I like to fiddle, to an extent (used to be a mechanic, way back), but in general my time at the range is limited and I'd like to enjoy shooting mostly, and not wonder if my latest batch of loads is going to be consistent.
9mm bullets are cheap, and life is short, to summarize
-pete