Re: 1 in 10 twist and 230 Hybrid?
My nothing special gen I Sendero (1:10") 300 Win Mag consistently shoots under >1" at 100yds. I have yet to work up a load or try it long range.
But, I think it's stabilizing just fine.
I'm near Dallas at ~500 ft.
Perhaps I just got lucky? But, it sounds like yours just doesn't like these bullets for whatever reason. Or, you just haven't hit the right combination.
Life's to short to force it if you can get something else to do the job.