system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why putting a spin on things makes them travel straighter (e.g. rifling with bullets)
gpt
Most bullets will not be perfectly symmetrical sure to flaws in the manufacturing process. These flaws will cause a bullet to naturally veer during flight. Think of a plane with the tail kinked slightly to one side, it will not fly sight without constant adjustment from the pilot. Since bullets cannot be stress once shot, one way to deal with this natural tendency to veer off is to spin the bullet to balance out the veering. If a bullet would normally veer slightly to the left, then spinning it causes it to spend half that time upside down as it were and it veers back to the right.

Think about an American football thrown in a spiral. The football is not a perfect ovular shape, because it has stiches on one a side that create increased drag. Spinning the ball causes those stiches to spend the same amount of time create drag in every direction rather than throwing it without a spiral where the stitches always stay on the same side.