How much H335 behind 123 gr SST?

[LRRPF52]

If it were me, I’d use the Hodgdon data for the SST’s. I believe the difference in charge weights is, the Hornady manual includes the GMX/CX all copper monolith bullets along with traditional cup and core bullets in the data. That means they have dial the charge weights back to accommodate the monoliths, which are harder to engrave in the rifling. To my knowledge there is no official “bolt gun” load data for the Grendel. The 6mm ARC is another matter.

This is the answer. If you look at the Hornady manuals since they started including the 120gr GMX with 6.5 Grendel data, that is the limiter.

Hodgdon’s is for the 123gr SMK, which is a much longer bullet as well.

H335 is a great powder for most bullet weights 85gr-123gr in 6.5 Grendel. If you look at Hodgdon’s data, it shows H335 generating the highest velocities with some of the lower chamber pressures, with one exception being under the 95gr V-MAX, where it generated the highest mv, and also slightly higher chamber pressure than the others at 50,200psi. Most of the others were under 50,000psi with fastest speeds.

The most comprehensive load data is in the 6.5 Grendel Reloading Handbooks we compiled, which includes AA, Hodgdon’s, Vihtavuori, Western, and various other tested combinations.