Not quite.Bullet expansion relies on velocity,impact media(what is struck) but it also varies greatly with bullet construction,which consists of far more than jacket thickness.A hollow point will generally expand much more rapidly than a lead tipped bullet.A ballistic tip expands quicker because the poly tip acts as a wedge driving the nose open.Jacket hardness matters just as much as jacket thickness.The hardness of the core is also a factor in some cases,but not all since some bullets have tungsten cores that do not expand at all.The monometal bullets such as the tsx have no jackets at all,so jacket thickness and hardness is obviously not a factor.

I have personally used ballistic tips for over 20 years for pronghorn,bighorn,whitetail,mule deer,elk and moose with no failures to date.And over that 20+ years,there have been several changes made to the ballistic tip line of bullets making the newer versions much tougher than the earlier versions.Judging the recent versions based on 20 year old versions is like shopping for a new vehicle using a 20 year old buying guide.