The LBX is clearly the latter effect only with bigger (and fewer) shot (vice darts/nails) with diminishing damage return over range
Exactly how did you come to this conclusion? It's clear LBX cannon don't fire fletchets, but why do you think LBX cannon has a diminishing damage return over range like a shotgun? A LBX-2 is one of the longest ranged air to air weapons and it doesn't lose any damage out to it's maximum effective range.
My experience is actual, as in real life, I have fired the things and the max eff range of a flechette fired from a canister round drops off significantly after 500m. The beehive disperses at a set range, so, from about 500m-3,000m (or more) it is closed, once the set range is reached, kablooie, flechette dispersal to about 200m or so radius.
The max range on the LBX2 is about 1,000m, once that max range is met, damage diminishes to zero. The distance a "round" travels in MW4 is set and once that max range is met, there is no damage, not very realistic considering that if you could "see" the target at 1200m, you could adjust aim and expect to hit the target because the munitions keep traveling past the max range (in real life, this would be true), but further down the ballistic trajectory to the point of insignificant damage (in the ground usually or a light tap against the target). My statement is true, but only in the real world. This is one of the things I dislike about the MW4 engine, you can only draw to a given range. We currently have tank and infantry weapons in reality that can shoot to 3,000m plus, why can't we get an engine to replicate that? I don't even know the max range you can engage a target in Crysis. Anyone? It draws out to 8km, can we shoot to 4,000m with a tank round? Current rail-gun tech has a goal of 4km/sec (read that somewhere years ago) 4,000m in one sec for a slug to travel downrange! by the 4th millenium, thy should have that capability.
max for a custom modded sniper-rifle is 2000m (~6570ft), (go for the dot).
And your right, the ballistics (or lasers) in a īMech game shot be able to travel further than itīs max range and still give damage. Itīs only the velocity that is degreased and the ballistic curve has to be set in a higher angle for a longer shot.