I carry the Speer 115 gr. Gold Dot.
I don't think 10 grains would make any appreciable difference between the
"punch" of the 124 gr. and the
"speed / Penetration" of the 115 grain. Especially with the short barrel length of the R9 and the "up-close-and-personal" distance between the muzzel and the target. :-/
So, I don't see any advantage / disadvantage to either choice of these two Gold Dots. Does this sound logical to you all? I'm still learning.