“Because this was a heavy bullet its trajectory was an arc.”
This is true for even very light bullets, or any unpowered projectile really, is it not?
___________________________________________________________
Yes, all bullets travel in an arc, sort of.
The reality is that they simply fall to the ground. If you were to shoot a gun level, and drop a bullet at the same time as you fired the gun both bullets would hit the ground at the same time.
Usually we think of an arc as going up and coming back down in a curve, half a sine wave if you will but the reality is more like a quarter sine wave. This is true of anytime you shoot either level or aiming below your straight line of sight. When you aim down it is possible to reach the ground with your bullet before the one you dropped at the same time, the speed of the bullet outruns gravity.
Some people think that a bullet falls when it runs out of energy from the firing in the gun, it is not true. The bullet starts falling the instant it leaves the barrel of the gun. It gets to its target simply because it is traveling horizontally faster than it is falling vertically.
I realize that all sounds counter intuitive but it is true.
I get that, but I always thought that, somehow, the spinning bullet develops lift which causes it to go upward a bit or at least retards its fall after leaving the barrel.
The old drop a penny at same time you fire a weapon horizontally.Bullet and penny will hit ground at same tine.