Reloading questions?

[leadpillproductions]

Ive been loading up a new load 265 lrx 338 ultra .
86.6 gr rl 25 3 shot average 2792
87.0 gr rl 25 3 shot average 2721
my question is why if more powder did I loose velocity ?

 

[boomtube]

Ive been loading up a new load 265 lrx 338 ultra .
86.6 gr rl 25 3 shot average 2792
87.0 gr rl 25 3 shot average 2721
my question is why if more powder did I loose velocity ?

That .4 gr is a bit less than .5% of a large powder change. Three rounds means little, statistically speaking. The normal E.S. of the two charges probably over laps more than than the 71 fps difference you cite.