Assuming the jacket stays intact, why would 40gr bullets fail to perform in 1:9 twist rifles?
It seems you can not over stabilize the lighter bullets in a fast twist, but you can certainly under stabilize the heavier bullets in a slower twist.
I've shot Sierra 40gr Varminter HPs in my Mossberg MVP Varmint with a 24" 1:9 barrel loaded out to 3700+ FPS with no issues.
I was worried that I'd wasted money on bullets that would vaporize upon leaving the muzzle, but they've proven to be very accurate at the 100 yard range I shoot at. I did call Sierra to ask if there were any velocity restriction on them and was told not to worry about it.