338 cheytac light loads?

[Sigma]

Current load is 135 grains h50bmg
300 grain sierra matchking
3200 fps out of a 34” brux barrel

looking to run my silencerco harvester big bore (which is rated up to 338 lapua)

so would be great to be able to load down and replicate lapua ballistics

Any input is appreciated, I am not new to reloading, but new to developing lighter loads/subsonic loads.

I know hangfires/detonation could be an issue if underfilled with a slow burning powder from what I’ve read? Hence why I am here to ask and to learn.

thanks fellas