I decided to try some retumbo in my 26" proof carbon barrel with 230 bergers. did a powder charge/ladder test at 580 yds. 4.5 gr spread in powder had 5" vertical. There was a couple nodes. Decided to try the one at 2945 fps. Loaded up 6 rounds and they had 1.4" vertical with a decent amount of mirage when i shot. 5 out of 6 had .9" vertical. The nice thing is even on the powder charge test the shots that weren't in the velocity node still landed in the same spot. retumbo definitely had a tighter vertical spread for that range of powders compared to some of the other powders Ive tested. Went and confirmed my 100 yd zero with a perfectly centered .113" group.