As far as I know, darts, arrows, and airplanes have the center of gravity(CG) ahead of their center of pressure(CP) and often have fins at the rear to achieve stability. Contrary to these, bullets have CP ahead of CG and they do not have fins. Thus, how do bullets acquire stability?

  • $\begingroup$ Just guessing here: rockets are pushed from behind to accelerate, while bullets are pushed from the front to decelerate....so it all makes sense? $\endgroup$ – JEB Jul 29 at 14:36

You may want to look up rifling - a bullet is made spin around it axis in order to give it stability. This is actually the main difference between a shotgun and a rifle - the former does not have a helical groove in its barrel and therefore is much less precise (although nowadays the distinction is probably rather blurred).

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  • $\begingroup$ can a spherical projectile of the pre-rifle days even be unstable? I mean if $I_{ij} \propto \delta_{ij}$.... $\endgroup$ – JEB Jul 29 at 14:38
  • $\begingroup$ @JEB I think by stability we mean something different when talking about projectile and a static object. The bullets are intended to fly straight into the target, being weakly sensitive to weather conditions, gravity, etc. I suppose one additional difficulty with round bullets is that it is hard to make them perfectly round, and prevent them from deforming by the time they exit the barrel. $\endgroup$ – Vadim Jul 29 at 14:44
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    $\begingroup$ @JEB: early 19th century muzzle-loading rifles used spherical projectiles - lead balls. They had much better accuracy than contemporary smooth-bore muskets. $\endgroup$ – RedGrittyBrick Jul 29 at 14:57

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