Well, I imagine it would be hard to do, as it’s using an actual projectile that is affected by gravity. Hence, it’s only going to align with the cross-hair at a specific distance (much like an actual firearm that is zeroed to a specific distance). I’d imagine raycasts would be more appropriate if you need the cross-hair to be zeroed at every distance. Now that you’ve mentioned it though, I’m curious to know how Battlefield 4 handles this, since it appears that actual projectiles (instead of raycasts) are used regardless if the firearm is being fired from the hip or down the sights.
Anyway, I’ve added some more videos to the original post. I’m back into the swing of things after an extended break (due to various frustrations).