David Tubb shoots the 6XC with H4350 powder. He comments: POWDER: I tried Hodgdon H4831 but could never get the velocity I wanted out of a 27-inch barrel; with this powder velocity without any brass flow (shiny spot) on the ejector plug was around 2930 fps. (4831 might be worth a try if one has a 32-inch barrel). I ended up with H4350 — the same powder I use with my 107 gr. Sierra bullets in this cartridge. I use the ejector plug brass flow as my pressure indicator — when I see a shiny mark on the case head I automatically back off the charge 1/2 grain. I have shot the DTAC 115 at over 3100 fps but saw too much pressure. I can shoot this 115 at 3050 fps and have a reloadable/reusable case; however, out of my 7.5 twist barrel it did not shoot as well as when I backed the load down another 1/2 grain to 39.6 gr. of H4350. This gave a velocity (depending on temperature) of anywhere from 2988 to 3020 fps. When I got home from Camp Perry I rechronographed the ammunition I used there and it was going 2990 fps (early morning, cooler temp.); mind you, this was several hundred rounds later in the barrel’s life.