[Svartalfiar]

I was wondering what ‘deceleration range’ was? I can imagine there is a little acceleration for a few centimeters outside of the barrel but then it is all friction afterwards.

I mean, if you want to get truly physics-al about it, deceleration would be slowing acceleration, which means negative jerk. Once the round leaves the barrel, it is constantly accelerating on a vector opposite the velocity vector due to drag, as well as accelerating down at an essentially constant acceleration due to gravity.

Off the top of my head, I would assume jerk is decreasing (so yes, deceleration) as the round slows, as the slower velocity means less drag and therefore less slowing as the round moves further.

As the round falls, however, acceleration will increase slightly as you get closer to the other mass (earth), but drag would likely overcome this positive jerk quickly, and the gravity vector of acceleration would be decelerating until you reach terminal velocity, at which point acceleration is zero.

So yes, pretty much 100% deceleration until you have your sudden stop.

[posterchild]

Which is why i question even using the term. A fired bullet decelerating is expected - like saying water at standard temperature and pressure is ‘wet.’