chasseur,

If the bullet hasn't stabilized, it will not make a perfect hole in the paper so it is
reasonably easy to tell if it has or not.

I never actually heard of a 9.3 x 74R not stabilizing 320gn (or similar) weight
bullets and 2 friends of mine use them OK on DG.

I think the Barnes X in 458 was one of the bullets that didn't stabilize quick enough
(due to its length) and this caused problems when hunting DG at very close quarters.
I will try to find the reference to this - it is written up somewhere.

500 Nitro