I've drawn and cataloged many Ideal/Lyman molds, as well as many custom target molds. You can check weights and lengths for those molds molds here:

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With that info, you can check for stability with this program that considers the bullet's nose shape and the CG to get the stability factor.

About the program:

History 
This program is basically a slick version of Robert McCoy's "McGyro" DOS program, written in the late 1980's when he worked for the U.S. Army Ballistic Research Laboratory at the Aberdeen Proving Grounds. It was later improved by William Davis Jr. of Tioga Engineering and the claim was an accuracy of 5% for super and subsonic velocities, and 10% for trans-sonic velocities.

Frank

Dave
To calculate the proper twist for a bullet, length is as critical a consideration as weight. A .322 diameter, 190 grain blunt nose bullet might be approximately .98 in length. A .322, 190 grain, long nose spitzer bullet might be approx 1.13 long. Run those bullet specifications through one of the calculators and you will find they take different rifling twists for stabilization.
Hope that helps

Hm - When I run it for my 0.95" long .308 bullet at 171grs, 1060 fps, it shows to be amply stable in my 1 in 15 twist - but the target doesn't agree...  There are signs of tipping.

MartiniBelgian,
If it's the 311403 bullet and you have a meplat close to the .2 that I posted for a members mold. you have a factor of 1.4, close to the edge of stability.

I agree with Dave about tipping. This is a 246 6c target I shot at Modesto, with sever tipping but, I've also shot a 249 w/o any tipping. Same rifle.

Frank

MartiniBelgian,
You can see in the Geoffrey-Kolbe program, how much subsonic effects the bullet stability. This is a graph of the .95 long 308403 bullet. I believe the normal length should be closer to .96 though and that would decrease stability, even more.

Frank