I've been using 54.5 grains of H4350 behind 130gr TTSXs, seated to 3.350″ COL, almost a “squeeze fit” in the magazine, but they do feed with no hassles. It's good for 3/4″ to 1″ at 200 metres from my T3 Super Varmint. Muzzle velocity 2900 fps. Good hunting !