Will 77 grain bullets stabilize in a 1:9 twist barrel?

[mikeinco]

it is all about LENGTH, not weight.
9 will stabilize some not all
plastic tips can cause issues,( hornady 75 match vs 75 amax)
all guns are different, change altitude, temp, humidity.
bbl lenght limits velocity.
problems show up quicker in shorter bbls

[charlie b]

One of the things that surprised me is that CFJunkie is nearer to sea level (and high humidity) and I am closer to 5000ft elevation (and low humidity) and we both see better groups with the 77gn bullets.

Sierra specifically states that their bullets should be used with faster twist barrels. 1:10 or faster for 69gn and 1:8 or faster for 77gn. I am assuming that Sierra is playing it a bit safe in case someone wanders out of the 'envelope', such as a high air density environment and marginal velocity.

FWIW, the 75gn Hornady ELD's also work with my 1/9 twist barrel, but, I have not tried them at 600yds, only 400yds.

PS it is not all about length. That refers to the simplified formulas for stability that assume a football shaped bullet at Mach 2.5. For actual calculations you need bullet shape details, as well as mass, to calculate things like polar and transverse moments.