Bullets precess (yaw) twice in flight, first when they leave the muzzle, then they stabilize only to yaw again upon impacting a denser than air object regardless of hardness or composition of the object. Stability in flight is dependent upon the center of gravity of the bullet coinciding with the geometric center of the bullet, and upon it's rotational velocity, which unlike its linear velocity, decays little during the time of flight. Upon impact the bullet's ability to regain stability so it can travel through the target in a stable trajectory is, by contrast, dependent on the position of its center of gravity along its length and on its rotational velocity. A boat-tail tends to balance the bullet more forward than a flat base which balances rearward. Likewise, a bullet with parallel sides tends to have its balance point near its linear center while a bullet with a secant ogive has its balance behind the point that a bullet with a tangent ogive would. Those folks who maintain the importance of a theoretical ideal rate of spin for any given bullet ignore the fact that the faster the bullet spins, the more rigid its stability is during the terminal portion of its trajectory, hence the deeper and straighter penetration tends to be. Thus in the discussion of terminal ballistics, when straight line penetration is desirable, a bullet from a 1:7 twist is preferable to one from a 1:12, provided the structure of the bullet is not compromised due to the greater centrifugal forces working on it as it deforms.
If we are talking about pure accuracy, there is no reason why a FMJ bullet cannot be as accurate as an expanding bullet, when both are manufactured within the same tolerances and a similar profile. Jacket uniformity, which effects the coincidence of the center of gravity and the geometric center of the bullet,is more important to accuracy than whether the bullet's nose is open or closed. Some FMJ bullets shoot very well, in fact my experience with a particular batch of Lapua .308/167 gr FMJs was nothing short of astonishing, as they decidedly out shot Sierra 168 MKs from my target rifle at 100, 500 and 800 yards. Those needle nosed mono-metal solids that Barnes manufactures in small bore calibers are quite accurate in some rifles, a pal of mine used them quite a bit in his .25/06 when hunting fur. Thus bullet construction has a much greater impact on terminal performance than on accuracy. A good bullet will shoot well, a poor one won't, provided that is, its chosen appropriately for the rifle its used in. When I acquired my son's rifle, which turned out to be a .270 (I was looking for a .30/06 but couldn't pass up the deal I could get on this .270) I immediately bought a few boxes of Woodleigh 180s to load for bear work. It didn't take much shooting to determine those bullets were inappropriate for use in his particular rifle, not that they were a poor bullet. But oblong bullet holes appeared in the target because those long bullets didn't fully stabilize in the 1:10 twist. Now it might be argued that bear defense is mostly a short range gig, and that marginal stability isn't a great issue, but bullet instability in the terminal portion of its trajectory could well become an issue when deep, straight line penetration is required for success.
Not all game is equal in density, and even game which has the densest body structure, is not uniformly dense. Hide is denser than viscera, bone is denser than hide, and blood is denser than the air pockets that surround organs and exist within the lungs. The resistance that the bullet encounters is a function of density, while its the construction of the bullet which determines how that bullet responds to the density. If resistance is slight, the bullet will slip through without much change to its shape, velocity, precession, or trajectory. But the denser the game, the more resistance the bullet encounters, and the greater the effect is on that bullet. Wolves tend to be long and lean, and one reason for their apparent toughness is that the bullet chosen might not upset as much as if it shall we say a pig of similar weight. Wolves are frequently shot while the hunter is in search of other game, thus the bullet he chooses is not specific to a 7' long animal that typically weighs quite a bit less than a third of the weight of an adult black bear.
