blackbear, The gun is a machine and you are correct in stating that the "gun does not" make a mistake. (although, it is not perfect, it was built by man, with many flaws, each flaw is a check mark against perfection) A tuning fork vibrates at the frequency (harmonic tone) it was designed to mimic! Unless, it to, is flawed, then it is useless to the musician. The issue is tweeking the components of the gun into compliance with the laws of physics (periodic wave). That makes "your mistakes" smaller. Have you ever heard someone say they have a gun that just really "likes to shoot"? That piece was one of those that has the harmonics to allow human error to be less critical. That then allows you, the shooter, to further refine your position, trigger control, sight picture, breathing and other considerations to become "one with the rifle"

! That may sound like some far Eastern mumbo jumbo, but, in fact, it is closer to a perfect description of the process than any other words I can use.
So, if you have a 'minute of piepan " rifle, that rifle will not allow you to shoot any better than its capability. It is then, the limiting factor. Your skill is limited to the statistical probability of what percentage of the shots will be in an acceptable zone, the cone of dispersion. No matter how much you practice with this gun, you will not shoot any better than it is capable of delivering.
Another example; If you were the national long range rifle champion, would you practice with a inaccurate, imprecise rifle. Would you show up at a match with one, expecting to win? Just some thoughts. Greg