Originally Posted by plouffedaddy
I don't understand it with irons either but it can be an issue with red dots & scopes (usually at < 100m)
That's true, I should have mentioned scopes. I only have 1 scoped rifle atm and never really use it at less than 75m, so never experienced any parallax issues with it. I also find it to generally be an issue on lower quality optics. For instance, I have never noticed parallax on my Aimpoint H-1 even at really close ranges.