I'm not refuting your argument, merely throwing my own theory into the fray. To better explain, I found a Wikipedia article (Wiki search: Rifleman's Rule) that illustrates my point. Quote "The bore angle is set to ensure that a bullet on a parabolic trajectory will intersect the LOS to the target at a specific range". Thus, it is not the recoil of a rifle that causes the arc of a bullet but a purposeful elevation of the bore angle to accommodate for a rifle zeroed beyond the range of a flat bullet trajectory.

I also think that part of Katanama's argument is misleading, at least for me. Quote "...as soon as the bullet [sic] have left the barrel it is not accelerating anymore therefore it does not exert a force on the gun" seems to give the impression that the bullet continues to cause recoil as it travels down the barrel, and that this recoil is only stopped when the bullet exits the barrel. On that assumption, I disagree, as primary recoil is only created by the initial firing of a bullet (Newton's Law), and at no other time does the bullet create a reaction in the gun from its forward momentum. I do, however, understand that he is talking about primary recoil when addressing a marksman's ability to control recoil, as this is the only opposite reaction that a) can be compensated for and b) affects the bullet's flight path. To better understand my own argument, I did another quick search and came upon a mathematics breakdown of firearm recoil at bsharp.org. I cannot, at this time, post the full URL as I'm a lurker, not a poster.

PS: I had to write this thing twice, because it erased my entire post when I tried submitting it with my sources in URL form. My original argument was MUCH more concise, d'oh!