Flat Shooting

It's popped up before.

We all talk about flat shooting rounds.  If you already know this stuff, tune out now.

Hardly anyone talks about what is meant.

We need to start with some basic physics.  This will be very broad strokes and is going to ignore some aerodynamics.

All other things being equal...  A bullet fired will fall to the earth at the same rate as a bullet dropped from the same height.

It's about half a second from shoulder height to the ground in 1g.

If fired horizontally a bullet fired from shoulder height will hit the ground the same half second later as one dropped from shoulder height.

If it's going 1,000 feet per second, that means it will hit the ground 500 feet down range.  2,000 feet per second will hit 1,000 feet down range, etc.

The faster your bullet is going, the straighter the arc the bullet is travelling along appears.  Thus "flatter".

It looks even flatter when you consider that your barrel is rarely parallel to the ground, but is almost always angled up relative to the line of sight.  Same arc, just rotated a bit, but the arc is the same and the faster bullet gives a shallower sagitta, appearing flatter than the sagitta of a round that needs to have the barrel much more elevated to get the same bullet impact.