Will 1/9 stabilize 36 or 43gr?

[kwr]

My 20" barrel 1 in 9" twist DPMS upper in .223 had no problem stabilizing the Walmart 45gr whitebox ammo.

[Josh3239]

Yep, Greenhill Formula. I saw it in the ABCs of Reloading. Length determines twist rate, not weight.

I saw this somewhere else and kept it for reference:

Twist rate is based on what length of bullet you are going to use, not the weight.

Twist = 15 X D2/L

Where:
D = bullet diameter in inches
L= bullet length in inches
15 = a constant

Now, why the bearing surface length is not considered I do not know but for 69gr SMKs, this formula gives you a 7.479 and for 55gr FMJBT's I get a 9.155. Both #'s are consistent with what is known to work well so I figure it works,