I'm not sure the exact numbers, since, currently, these are hidden from the player, but it seems to be that whatever malus they use to try and balance out horseback riding (the same one that you can remove slightly through perks) also affects weapon length.
In example, a man on horseback has a polearm, if you stab it at a man with any one-handed weapon, especially when charging him, you will passthrough the hitbox slightly with the weapons model, but no hit is registered. At the same time, they can hit you with no issue. Of course, it's hard to prove this is because the malus to melee weapons, I don't know the code, nor know enough to look at it myself, but this seems, from an outside perspective, to be the case.
This can also be slightly noticable with couching weapons, though it's much, much harder to tell if you simply didn't miss with the exact point of the weapon, the only way to do dmg, since you are going so fast.
In example, a man on horseback has a polearm, if you stab it at a man with any one-handed weapon, especially when charging him, you will passthrough the hitbox slightly with the weapons model, but no hit is registered. At the same time, they can hit you with no issue. Of course, it's hard to prove this is because the malus to melee weapons, I don't know the code, nor know enough to look at it myself, but this seems, from an outside perspective, to be the case.
This can also be slightly noticable with couching weapons, though it's much, much harder to tell if you simply didn't miss with the exact point of the weapon, the only way to do dmg, since you are going so fast.
